Category: Chemistry Notes PPT

To explain acid-base reactions, the first acid-base theory was given by Svante Arrhenius in 1884 in his work of establishing the presence of ions in an aqueous solution for which Arrhenius received the Nobel Prize in Chemistry in 1903. Arrhenius describes acid as a substance that contains hydrogen or produces H+ in an aqueous solution. While he described bases as that substance that contains hydroxyl groups or produces OH– in an aqueous solution. In 1923, Bronsted – Lowry’s theory of acid-base was proposed by Johannes Nicolaus Bronsted and Thomas Martin Lowry independently. According to this theory, an acid is a substance that donates protons while a base is a substance that accepts protons. In the same year (1923) American Physical Chemist Gilbert N. Lewis proposed an alternate theory to describe acids and bases. His theory was widely accepted by chemists and scientists as by using Lewis acid and base concept they are now able to predict a wider variety of acid-base reactions. 

What is Lewis Acid? 

According to Lewis’s theory of acid–base reactions, “a species that has vacant orbitals and can accept an electron pair is called Lewis acid.”

An electrophile is a Lewis acid as it is an electron-deficient group and can accept electrons easily. Acid uses its lowest unoccupied molecular orbital (LUMO) to form bonds with bases. 

Examples of Lewis Acids 

Few examples of Lewis acids are listed below –

• All cations are Lewis acids. For example, Cu+2, Zn+2, Fe+2, Fe3+ etc. are Lewis acids as they can accept electrons. 

• H+ ions can be considered as Lewis acids. 

• An atom or ion or molecule with an incomplete octet of electrons can act as a Lewis acid. For example, AlF3 (Aluminum fluoride).

• Molecules whose central atom can have more than 8 electrons in a valence shell and can accept electrons, can be called Lewis acid. For example, SiBr4 and SiF4.

• Molecules that have multiple bonds between atoms of different electronegativities act as Lewis acids. For example, CO2, SO2, SO3 etc. 

Applications of Lewis Acids

Lewis acids are used in many reactions as catalysts. In Friedel – Crafts alkylation reaction, AlCl3 accepts a chloride ion lone pair and forms AlCl4- and creates strongly acidic electrophilic carbonium ions. The reaction is given below –

RCl + AlCl3 🡪 R+ + AlCl4–

Apart from this Lewis acid’s action can be seen in photochemical (CO2 reduction), electrochemical, hydrogenation, and Prins reactions.  

What is Lewis Base?

According to Lewis’s theory of acid-base reactions, “a species that has a lone pair of electrons and can donate an electron pair is called Lewis base.”

A nucleophile is a Lewis base as it is an electron surplus group and can donate electrons easily. The base uses its highest occupied molecular orbital (HOMO) to form bonds with acids. 

Examples of Lewis Bases 

A few examples of Lewis bases are listed below –

• Any molecule, atom, or ion with a lone pair of electrons can act as Lewis bases. For example, NH3, H2O: etc. act as Lewis bases. 

• Anions can donate electrons, so they act as Lewis bases. For example, H–, F–, OH–, CN–etc. act as Lewis bases. 

• Pyridine and its derivatives act as Lewis bases.

• The pi-electron systems which are rich in electrons act as Lewis bases. For example, benzene, alkenes, alkynes, etc. can act as Lewis bases. 

• Complex anions such as sulfates also behave as Lewis bases. 

Applications of Lewis Bases 

Lewis bases are used to enhance the activity and selectivity of metal catalysts. They are used as ligands in coordination chemistry. Few Lewis bases are “multidentate” so they can form multiple bonds with Lewis acids. These Lewis bases are called chelating agents.  

Chemical Reactions between Lewis Acids and Bases 

Lewis acid accepts electrons from the Lewis base and the formation of Lewis adducts takes place. A dative bond is formed between them. Dative bond is also called a coordinate covalent bond or coordinate bond. A few examples of reactions between Lewis acids and bases are given below –

• Reaction of SO2 (Lewis acid) and O2- (Lewis base) – Non – metal oxides such as sulfur dioxide acts as a Lewis acid and accepts an electron pair from oxide ion, thus forming a dative bond and an acid – base adduct (oxyanion). Reaction is given below –

• Displacement Reactions of Lewis acids and bases – Many Lewis acid – base reactions are displacement reactions. In these reactions, Lewis base displaces another Lewis base from an acid base adduct. Reactions are given below –

This was a brief on Lewis Acid and Base, if you are looking for detailed study notes or solutions of NCERT Textbook problems based on this topic, then log on to website or download Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Study notes, Revision notes, Mock Tests and much more.

Learning Lewis Acid and Lewis Base – Examples, Applications and Chemical Reactions?

Studying Lewis Acid and Base – Examples, Applications and Chemical Reactions will require a lot of your time and attention. You have to create a proper study plan to start learning this vital concept of chemistry. By learning this concept, you can ensure great marks in the chemistry exam. To start learning this topic, you can follow the tips mentioned below. 

• Start learning Lewis Acid and Base – Examples, Applications and Chemical Reactions with your textbook and read the explanations of every topic thoroughly to get an idea of what this concept is about. 

• Use ’s learning platform to download the necessary study material you need to understand the concept of Lewis Acid and Base – Examples, Applications and Chemical Reactions.

• Before you start learning Lewis Acid and Base – Examples, Applications and Chemical Reactions, you should have a clear understanding of acids and bases and their uses, structures, and properties. 

• Make notes of all the important points that you find while studying the concept of Lewis Acid and Base – Examples, Applications and Chemical Reactions. These notes will help you summarize the concept and assist you in quick revisions before the exam. 

• Once you have completed studying Lewis Acid and Base – Examples, Applications and Chemical Reactions, you should use the questions given in your textbook and reference guides to practice and enhance your knowledge of the topic. 

• Refer to sample papers and previous year question papers of chemistry to understand the difficulty level and different types of questions related to Lewis Acid and Base – Examples, Applications and Chemical Reactions that can come in your final exam. 

• Try to learn and memorize the chemical names of all the formulas and compounds used in Lewis Acid and Base – Examples, Applications and Chemical Reactions.  

Lithium chloride is a chemical compound with a chemical formula “LiCl”. The salt is a normal ionic compound, although the Li+ ion is small in size, it produces unrecognized effects for other alkali metal chlorides, such as exceptional solubility in polar solvents and its hygroscopic properties.

IUPAC Name: Lithium chloride

Synonyms: 

• Lithium chloride (LiCl)

• Lithium chloride

• LiCl

Molecular Formula: LiCl or ClLi

Molecular Weight: 42.4 g/mol

Properties:

1. Physical Properties of Lithium Chloride Licl:

• It is Deliquescent in nature, appear as cubic crystals, granules or crystalline powder

• It has sharp saline taste

• It has Boiling point of 2417 to 2480 °F at 760 mm Hg

Its Melting point is 1121 °F 

• It has Density of 2.068 at 77 °F

• Aqueous solution of lithium chloride is neutral or slightly alkaline 

• Solubility: Very soluble in water alcohols, ether, pyridine, nitrobenzene

2. Chemical Properties of Lithium Chloride Licl

When Lithium chloride reacts with sulfuric acid, it forms lithium sulfate and hydrogen chloride. 

The chemical equation is given below.

[ 2LiCl + H_{2}SO_{4} rightarrow 2HCl + Li_{2}SO_{4}]

When lithium chloride reacts with sodium hydroxide, it forms lithium hydroxide and sodium chloride.

[ LiCl + NaOH rightarrow LiOH + NaCl]

Licl structure: lithium chloride structure

()

Licl Lewis Structure:

lewis dot structure for Licl is shown below:

()

Step-by-Step Explanation of How to Draw the Lithium Chloride Lewis Structure

Lithium chloride structure licl is drawn with the help of lewis dots

Lithium chloride is ionic compound, in which Lithium is a metal compound and chloride is a non-metal. Where electrons are transferred from metal ion to non-metal ion.

One electron is transferred from lithium and makes it electro-positive and by gaining one electron from lithium, chlorine becomes electronegative.

Preparation:

• Lithium chloride is prepared by treating lithium carbonate with hydrochloric acid. It is the highly exothermic reaction of lithium metal with either chlorine or anhydrous hydrogen chloride gas. 

• When hydrate is heated along with a stream of hydrogen chloride, then anhydrous LiCl is produced 

Uses of Lithium Chloride Licl:

1. Lithium Metal by Electrolysis

Lithium chloride is primarily used at 450 ° C (842 ° F) for the preparation of lithium metal by electrolysis of a LiCl / KCl.

2. As Brazing Flux

Lithium chloride is also used as a brazing flux for aluminum in automobile parts. 

3. Other Lithium Chloride Uses:

As desiccant in drying air streams.

lithium chloride is used in organic synthesis. For example, as an additive in the Stille reaction. 

Biochemical Applications: 

LiCl is used to precipitate RNA from cellular extracts

As a flame colorant, Lithium chloride is used to produce dark red flames.

Lithium chloride: it is used as a Relative humidity standard in the calibration of hygrometers and itself can be used as a hygrometer. 

Molten LiCl is used for the preparation of lithium niobite, graphene and carbon nanotubes.

LiCl has strong acaricidal properties (Varroa destructor in populations of honey bees)

Magnetic properties of solids in Chemistry, otherwise known as magnetism, arise from the magnetic dipole moment in solids. This magnetic dipole moment in magnetic materials appears from the spinning of electrons in its axis and orbital motion around the nucleus of the atom. The magnetic properties of solids are observed due to the magnetic fields created by electrons’ magnetic moment and electric currents. The magnetic property of solids is only one aspect of electromagnetism. The small charge of an electron generates a magnetic field along its axis. The magnetic moment is produced due to the angular momentum of the spinning motion of the electron.

What are the Main Properties of a Magnet?

Any substance that is capable of creating an invisible magnetic field is called a magnet. The three main properties of a magnet are:

1. The attractive property- As we already know that a magnet attracts other ferromagnetic materials. This is happening because of the attractive property of a magnet.

2. The repulsive property- There are two magnetic poles in any magnet. The similar magnetic poles will attract each other while the dissimilar magnetic poles will repel each other. This repulsion is due to the repulsive property of a magnet.

3. The directive property- Everybody has seen a compass. But the fundamental reason behind its working is due to the directive property of a magnet; this property states that a freely suspended magnet will always point towards the north-south direction.

Types of Magnets 

There are essentially two types of magnets that are present in the world:

1. Natural magnets- The magnets which occur naturally and have an inherently permanent magnetic field are called natural magnets. One example of a natural magnet is lodestone.

2. Artificial magnets- All the other types of magnets which are formed by electromagnetism come under artificial magnets. Artificial magnets work on the molecular theory which states that every molecule has a magnetic substance, whether it is magnetised or not.

What is a Magnetic Field?

A magnetic field is a vector field, which means that it has a specific direction of movement and strength or magnitude. It determines the magnetic impact on electric charges and currents, and other magnetic materials. A magnetic field can be obtained by passing electric charge or current and is directly proportional to the magnetic movement.

What is the Intensity of a Magnetic Field?

Simply put, a magnetic field intensity is an evaluation of how strong or weak any solid’s magnetic field is. It is denoted by H and refers to the amount of force that is induced by the unit’s north pole at any specific point in the magnetic field. The SI unit of the intensity of a magnetic field is equivalent to Ampere/meter or A/m. The direction of the magnetic field is usually derived by drawing a tangent on the line of forces that are experienced at a given point.

Some of the common concepts that are derived from understanding the intensity of a magnetic field are:

• Magnetic Pole Strength- It is denoted by the symbol p and refers to the quantity of the strength of the poles of any bar magnet.

• Magnetic Movement- A solid experiences a certain amount of rotational force in an external magnetic field. The measurement of this quantity is known as the magnetic movement. Therefore, it is possible to find the magnetic movement in any loop of an electric current or an electron that revolves around an atom.

 

What are Some Common Applications of an Electromagnet?

Electromagnets are used worldwide in various electronic products- both big and small.

Some of the applications of electromagnets are discussed below-

1. Everyday home uses- From doorbells to induction cookers, almost all the appliances that are used in the everyday working of a housework under the principle of electromagnetism

2. Medical field applications- Electromagnetism is exclusively used to build an MRI machine, which uses electromagnets to perform scans of the human as well as animal bodies. MRI, hence, stands for Magnetic Resonance Imaging.

3. Used in computer hard wares and other memory storing devices- All the information that is stored in a computer, laptop, phone, or any kind of hard disk is stored in the form of bytes or bits that are electromagnets. The computer hardware has a magnetic tape that works on the fundamentals of electromagnetism.

4. Used in various communication devices- The everyday mobiles and telephones that we use to perform long-distance communication with other people work on the principle of electromagnetism- through the interaction between different signals and electromagnetic pulses.

Classification of Magnetism

Different solids can be classified into several groups depending on their magnetic properties. The classification can be given as:

This category of substances are solids that are weakly repelled by magnets. The materials with diamagnetism have all paired electrons. Hence, the magnetic dipole moment is cancelled.  Examples of diamagnetic substances are H₂O, TiO₂, NaCl, and V₂O₅, etc. These substances have a small magnetic dipole moment which is opposite to the magnetic field.

()

These substances are strongly attracted by the magnetic field. They can also be permanently magnetized. The ions of ferromagnetic substances group together in small regions to act like a tiny magnet. This small magnetic region is called a domain. Upon application of a magnetic field, these domains are oriented in the same directions. Even after the removal of the magnetic field, the domains remain oriented to form permanent magnets. Some examples are Fe, Co, Ni, etc.

Solid substances that are weakly attracted by a magnetic field are called paramagnetic substances. They are magnetized in the same direction as the magnetic field. These are not permanent magnets. Paramagnetism is caused when one or more unpaired electrons are attracted by the magnetic field. So, they are temporary magnets. Some examples of paramagnetic substances are O₂, Cu²⁺, VO, VO₂, CuO and TiO, etc.

()

These substances possess a net zero magnetic moment. However, they have the same domains as ferromagnetic substances. Since these domains are oppositely oriented they cancel out each other and result in zero magnetic moments. MnO, V₂O are examples of antiferromagnetic substances.

These substances possess little magnetic moment. Here, the magnetic moment of the domains of the substances is aligned in parallel and antiparallel directions in unequal numbers. The examples are magnetite and ferrites.

Electrical and Magnetic Properties of Solids

As stated earlier, the electrical and magnetic properties of solids are two different aspects of a single phenomenon, known as electromagnetism. Solids all have different electrical conductivities. Conductivity is the property of an object to conduct electricity. Other such electric properties of solids include resistivity, capacitance, and impedance. Metals and alloys are great electric conductors, whereas ceramics and glasses are good insulators. Semiconductors have both electrons and holes in them to contribute to current. Materials such as aluminium, tin, metal alloys, and heavily doped semiconductors also exhibit superconductivity at low temperatures. 

The Origin of Magnetic Properties in Solids

To explain the origin of magnetic properties in solids, the electrons orbiting inside atoms of the object are considered. Magnetism originates from the rotating and orbital motions of the electrons. Just like the current flowing through solenoids generates a magnetic field, the charge of an electron causes a magnetic moment from the spin rotation of the electron. 

This magnetic moment is known as the Bohr magneton(µB), the smallest unit of the magnetic moment of solids. The value of Bohr magneton is equal to 9.27 × 10^-27 A m². Since only two electrons with up and down spins occupy an orbit, the magnetic moment generated is cancelled out. Only in the case of transition elements with not fully occupied d- orbital and rare earth elements with not fully occupied f- orbital magnetic moments due to spin rotation appears. 

Introduction to Measurement of Enthalpy and Internal Energy Change

Normally, the measurement of enthalpy and internal energy change is carried out by an experimental approach called calorimetry. These techniques are established on thermometric procedures which are done in a vessel known as calorimeter that is submerged in a known liquid volume. The heat which is evolved in the procedure is evaluated by using known heat capacities of the calorimeter and liquid by quantifying the difference in temperatures.

Notably, there are two separate conditions under which enthalpy and internal energy can be measured. These include constant pressure called enthalpy and constant volume termed as internal energy.

Before moving on with the measurements, however, you must know what enthalpy is , and difference between enthalpy and internal energy.

What is Enthalpy?

The heat energy, which is evolved or absorbed during a chemical reaction progression, is called enthalpy. It is represented by H, and the letter H indicates the energy amount. Enthalpy change is given by ΔH where delta symbol shows the change and its unit is joules or kilojoules.

It can be said that sum of internal energies of the system is enthalpy. The reason is that a change in internal energy takes place at the time of chemical reaction, and this change is calculated as enthalpy. It can be given by the following expression:

H = U + PV

Where H = enthalpy,

U = sum of internal energy,

P = pressure of system,

V = volume of system.

So, enthalpy is the addition of internal energy and energy needed to conserve a system’s volume at a given pressure. PV represents the work that is required to be done on environment to create space for system.

What is Internal Energy?

A system’s internal energy refers to the addition of potential and kinetic energy of that particular system. The stored energy is potential energy and the energy released due to movement of molecules is kinetic energy. Moreover, internal energy is represented by U and change in internal energy is given by ΔU.

At constant pressure, internal energy and enthalpy are same for a particular system. Internal energy change can take place in two ways. One because of transfer of heat – a system can absorb or release heat, and the second is by doing work. Hence, internal energy change can be expressed by the following equation:

ΔU = q + w

Where ΔU = internal energy change,

q = transfer of heat,

w = work done by or on a system.

Enthalpy Change Measurement

As ΔH is expressed as the flow of heat at constant pressure, calculations done using a calorimeter of constant-pressure (a system utilised to measure changes in enthalpy during chemical reactions at constant pressure) gives out direct value of delta h enthalpy. This apparatus is appropriately suitable for studying reactions which are carried out in solution at fixed atmospheric pressure. In general laboratories of chemistry, a “student” version named coffee-cup calorimeter is frequently encountered. The commercial calorimeters also function on a similar principle. Still, they can be utilised with solutions of smaller volumes, having better thermal insulation and can detect temperature change as little as like 10-6 degree Celsius. As the heat absorbed or released at fixed pressure is equivalent to ΔH, the relation between ΔHrxn and heat is:

ΔHrxn = qrxn = -qcalorimeter = -mCsΔT

Constant pressure calorimeter usage is shown in the following figure.

(Image to be added soon)

This coffee-cup calorimeter is a simplified version of calorimeter of constant pressure consisting of two nested Styrofoam cups and closed with a stopper which is insulated to isolate the system thermally from the surrounding environment. Between the two stopper holes, one is for the stirrer which will blend the reactants, and the second one is for utilisation of a thermometer to calculate the temperature.

Take a look at the following example to understand the calculation of enthalpy change clearly.

Example: In a coffee-cup calorimeter, 5.03 g of solid potassium hydroxide is dissolved in distilled water of 100.0 mL, and the liquid temperature rises from 23.0 degree Celsius to 34.7 degree Celsius. The average density of water in this range of temperature is 0.9969 g / cm3. What will be the delta h enthalpy in kilojoules per mole? Imagine that a negligible amount of heat is absorbed by the calorimeter and due to high volume of water; the solution’s specific heat is equal to pure water’s specific heat.

Substance mass, solvent volume and initial and final temperatures are provided in the question, and ΔHsoln is required to be evaluated.

Strategies:

• Calculation of mass of solution from its density and volume, and evaluation of change in temperature of the solution.

• Determining the flow of heat that goes along with dissolution reaction by putting the suitable values in equation qcalorimeter = mCsΔT.

• Using KOH’s molar mass to evaluate ΔHsoln.

Solution:

To evaluate ΔHsoln, first, you need to determine the heat released amount in the experiment of calorimetry. So, the mass of solution is:

(100.0 mL H2O) (0.9969 g / mL) + 5.03 g KOH = 104.72 g

The change in temperature is = (34.7 – 23.0) degree Celsius = + 11.7 degree Celsius

As the solution is not much concentrated (near about 0.9 M), it can be assumed that specific heat of the solution is similar to that of water. The flow of heat that goes with dissolution is:

qcalorimeter = mCsΔT = (104.72 g) (4.184 J / g ⋅ C) (11.7 C) = 5130 J = 5.13 lJ

The solution’s temperature increased as the solution absorbed heat (q > 0). However, from where did heat come from? It was generated by potassium hydroxide which was dissolved in water. 

ΔHrxn = – qcalorimeter = -5.13 kJ

This experiment shows us that when 5.03 g of potassium hydroxide is dissolved in water, 5.13 kJ of energy is also released. As the solution temperature increases, potassium hydroxide dissolution in water has to be exothermic.

The final step is to make use of molar mass of potassium hydroxide to evaluate ΔHsoln – heat generated after dissolving one mole of potassium hydroxide:

ΔHsoln = (5.13 kJ / 5.03 g) (56.11 g / 1 mol) = − 57.2 kJ / mol

Change in Internal Energy Measurement

In chemical reactions, change in internal energy at constant volume is calculated using a bomb calorimeter.

In this apparatus, the bomb (inner vessel) and its covering are made up of strong steel. The cover is sealed tightly to the bomb with the help of metal screws and lid.

The following is an image of a bomb calorimeter.

(Image to be added soon)

A certain amount of a substance is taken in the cup of platinum linked with electrical wires for creating an arc to ignite combustion. After that, the vessel is tightly closed, and pressure is exerted by putting excess oxygen. The vessel or bomb is submerged in water, in the calorimeter’s inner volume. The stirrer which is placed in the area between the bomb and calorimeter wall is used to uniformly stir the water. Upon striking the substance by electrical heating, the reaction begins.

The amount of substance which is burnt in the vessel by oxygen is known. The calorimeter and water in which the vessel is submerged, absorb the heat released at the time of reaction. Temperature change is evaluated by a Beckman thermometer. As the bomb is sealed, the volume of the same does not alter, and therefore, measurement of heat is equivalent to combustion heat at a fixed volume (ΔU)c.

The amount of heat released in the reaction (ΔU)c is similar to total heat absorbed by water and calorimeter.

So, absorption of heat by calorimeter can be expressed as:

q1 = k . ΔT

Where k = calorimeter constant which is equal to mc Cc (mc is calorimeter’s mass, and Cc is calorimeter’s heat capacity)

Now, absorption of heat by water can be written as:

q2 = mw Cw ΔT

Where, mw is water’s molar mass, and Cw is water’s molar heat capacity (4.184 kJ K-1 mol-1)

Hence, ΔUc = q1 + q2

= k . ΔT + mw Cw ΔT

= (k + mw Cw) ΔT

Following Are Some Uses Of Bomb Calorimeter:

• This type of calorimeter is utilised to decide heat release amount in burning reaction.

• It can be used to find calorific food value.

• Bomb calorimeters are used in several industries like food processing, metabolic study, testing of explosives, etc.

Measurement of enthalpy and internal energy change is an important part of thermodynamics. If you wish to know more related concepts and attend our online interactive sessions, download our app for easy access.

The tabular arrangement of the chemical elements by increasing atomic number to see the trends in their properties is called a periodic table. The Russian scientist Dmitri Mendeleev is credited with inventing the periodic table (1869). The modern table is derived from Mendeleev’s form of the table, but has significant differences.  Mendeleev’s version placed and ordered the elements according to increasing atomic weight rather than atomic number. 

How do we figure out the position of elements in the periodic table? Elements are natural extracts that we yield naturally and some are made synthetically but the original form has to be extracted no matter what. The most important characteristic of an element is that it cannot be broken down into any other substance and that is why it is written that it is extracted in its original form. Each element, which is about 100, has its own type of atom because every matter contains atoms and then ultimately everything in the universe contains at least one or more elements. 

The periodic table then places or lists all the known elements together with the similar properties and in a sequential manner. Periodic table helps us to identify those elements based on their property which can also indicate to us their weight, whether it is a normal element or comes under noble category etc.

Organization of the Elements

The arrangement and structure of the periodic table makes it easier and accessible for us to see the link and relationship between the elements at a glance, it is helpful in quickly locating the elements and in turn attach our own heuristics to learn the table as well. It is a basic step before we enter the chapter and read about the elements in detail, so the periodic table gives us a brief idea about the elements in the shortest form possible.

 

Elements and Classification

The elements have one form of classification where they are broadly classified as metals, nonmetals, and metalloids. Metals and non-metals are generally heard of but here we will also study the intermediate type of elements called metalloids. This type of classification is based on the shared physical and chemical properties.

 

A jagged black line in a periodic table (see figure below) along the right side of the table separates the metals from the nonmetals. To the right of the line lie nonmetals, the metals are to the left of the line(except hydrogen, which is a nonmetal), and the elements which lie immediately adjacent to the line are the metalloids.

Metals – What are Metals?

A metal is generally a hard solid substance that has a shiny luster and it conducts heat and electricity. Metals are good conductors of heat and electricity. Silver is the best conductor of heat. Metals also possess malleability, that is they can be hammered into sheets. Metals being ductile can be drawn into wire. At room temperature, most of the metals are solids and have a characteristic silvery shine (except for mercury, which is a liquid). 

The melting points of metals are usually high but gallium and caesium are those metals having such low melting points that they will melt if you keep them on your palm. Another exception to general characteristics of metals is alkali metals such as lithium, sodium, potassium which are so soft that they can be cut with a knife. Also, they have low densities and low melting points. Lead, mercury, titanium, chromium are bad conductors of heat. Bismuth is the poorest conductor of heat.

Metals Definition

A metal can be defined chemically as an element that readily forms positive ions (cations) and has metallic bonds. They tend to lose electrons easily. While the traditional definition focuses on the bulk properties of metals, they are sometimes also described as a lattice of positive ions surrounded by a cloud of delocalized electrons.

The Reactivity Series

The reactivity series is a series of metals where the arrangement is done in the order of their decreasing activities. It is developed after performing displacement experiments.

Non-Metals – What are Nonmetals?

Nonmetals are those elements that generally lack the properties of metals or have their properties opposite to that of metals. Their thermal and electrical conductivities are usually poor. They are brittle and do not possess the properties of malleability and ductility. Elemental nonmetals mostly are in a gaseous state at room temperature, while others are solids. Bromine is a non-metal which is liquid. Non-metals lack the shiny lustre except iodine. 

Generally, nonmetals have low melting and boiling points. Carbon is a nonmetal that can exist in different forms called allotropes. Diamond is an allotrope of carbon and is the hardest natural substance known and has a very high melting and boiling point. So it is an exception in the case of nonmetals. Also graphite, another allotrope of carbon is a good conductor of electricity which is another exception. Non-metals are less dense as compared to metals.

Nonmetals Definition

Non-metals are elements that form negative ions(anions) by accepting or gaining electrons. They generally have 4, 5, 6, or 7 electrons in their outermost shell so they tend to gain electrons during chemical reactions.

Metalloids – What are Metalloids?

The metalloids are intermediate in their properties between metals and nonmetals. Taking physical properties into consideration, they are more like nonmetals, but under certain circumstances, contrary to the expected behavior many of them can be made to conduct electricity. These semiconductors find their use in computers and other electronic devices. 

They can have a dull or metallic appearance. In a periodic table, these elements run diagonally. They are usually brittle. They form alloys with metals. They can both gain or lose electrons in a chemical reaction. Due to their unique properties, they find their use as catalysts, biological agents, flame retardants, alloys, and semiconductors in industries. Boron, silicon, germanium, arsenic, tellurium, and antimony are some commonly known metalloids.

Metalloids Definition

Metalloid, in chemistry, is a term that describes a chemical element forming a simple substance having properties intermediate between those of a typical metal and a typical nonmetal. They are often called semi-metals.

Comparative Study of Metals, Nonmetals, and Metalloids

In turn, there are Four New Elements that are  Added to the Periodic Table

Periods

There are a total of seven rows of the periodic table, which are called periods The increase is from left to right across a period. Elements on the left side of a period are metals and those on the right side are nonmetals. Moving down a period on the table adds a new electron shell.

Groups

The columns are addressed as groups or families. Right from the alkali metals to Noble gases, groups are numbered from 1 to 18 with the former being for the alkali metals and the latter for Noble gases. Elements with a  common group share a valence electron configuration. Elements display a pattern with respect to the atomic radius, electronegativity, and ionization energy. The atomic radius increases as the elements in succession gain an electron energy level.

Similarly, as we go down the Electronegativity decreases as we add an electron shell which basically pushes the valence electrons from the nucleus. Usually, elements have successively lower ionization energies when we move down the group, the reason being the easier removal of an electron from the outermost shell. 

Blocks

This section of the periodic table indicates the outer electron subshell of the atom. As we begin, we come across the S- Block which includes two groups named hydrogen, and helium. Then comes the p-block which includes elements or groups 13 to 18. Moving ahead we come to the d-block which includes groups 3 to 12, which are transition metals. Lanthanides and actinides are categorized under f-block, which is below the main body.

Conductivity

The ability to measure an aqueous solution to carry an electric current can be defined as conductivity. When put in a scientific manner it is the ability to transmit heat, sound, or electricity. So for eg. We can say that the conductivity in the water will be higher because of the concentration of ions. So, when we measure the conductivity of water, we basically and indirectly measure the concentrations of dissolved salts, bases, and acids. The conductance of a material. 

Ductility

This is defined as the ability of a material to be drawn or plastically deformed without fracture. It, therefore, indicates the softness or malleable the material is. The ductility of steel varies on the types and levels of alloying elements present. The quality or state of being ductile can be said as its shape changed without losing strength or breaking. When alloys are added to the metal, it improves hardness and strength can be improved without decreasing the ductility.

Malleability

the state of being malleable, or capable of being shaped, as by hammering or pressing, in simple words how a metal or anything can be moulded into any required shape without changing its properties is called the malleability of the element. Metal such as Gold, aluminium, and iron are examples among many other malleable elements that are used in our lives which we mould accordingly and use as per our convenience.

Are Metalloids Essential for Life?

Metalloids can be considered of vital importance to human health, plants, and all other living organisms. Some of the metalloids like boron, selenium, and silicon are beneficial or essential for healthy plant growth, whereas others, like arsenic and germanium, are highly toxic. Typically Metalloids have a metallic appearance but they are brittle, which is anything hard but is liable to break easily.  Along with this property, they also tend to be very good conductors of electricity.

Conclusion

This is all about the different elements and their types in the periodic table. Learn the different features of these types of elements and understand how they are categorized. Hence, focus on the properties and understand how they are organized to form a periodic table.

Minerals are substances or materials found in the Earth’s crust or in the atmosphere or in our surroundings having some definite chemical and physical properties. These substances become resources when there is some economic value added to it. Hence mineral resources are substances found in the earth’s crust and have some economic value.   

There are some minerals which are less reactive and hence can be found as a molecule of that particular element, for example, Gold, Platinum etc. while others are found by the various compositions of different elements. Identification of greater than two thousand minerals have been done, most of which are inorganic compounds formed by some combination of the eight basic minerals which are Sodium (Na), Potassium (K), Aluminium (Al), Oxygen (O), Iron (Fe), Silicon (Si), Calcium (Ca), and Magnesium(Mg). One important fact to note here is that around 98.5% of Earth’s crust is made up of these 8 minerals.

Existence of Mineral Resources

Mineral resources generally found in the environment need to be extracted and its cost of extraction in accordance with its economic value that determines whether a particular substance will be regarded as a resource or not. For example there are many rocks in which iron is found but we call a rock to be an iron ore when the extraction of iron from the rock is feasible. 

Characteristics of Mineral Resources

• Quantity and quality of mineral resources are inversely related i.e. if we get good quality of a mineral then it is likely that we will not get enough quantity of the resource. 

• Mineral resources are exhaustible by nature. They take a long time to develop but take less time to be used so as a result there is net depletion of these resources. And hence they need to be used in a sustainable way so that they get enough time to develop and hence remain conserved.

• Mineral resources are crucial in the development of a country. Large scale industries or the manufacturing sector are more often than not dependent on mineral resources.

Categories of Mineral Resources

When we talk about mineral resources we generally classify mineral resources in two categories:- 

1. Metallic resources and

2. Non-metallic resources

Metallic Resources

Metallic resources consist of substances like gold, silver, tin, lead copper etc. Finding and extracting some of these resources requires knowledge and application of different sciences while few others can be extracted relatively easily or needless processing. 

Classification of metallic resources 

1. Ferrous minerals 

2. Non-ferrous minerals 

This component of metallic minerals contains iron as a dominant part of the ore. 75% of the total production of ferrous minerals constitute this component. Examples include iron ore, nickel, chromium etc.

As the name suggests, this component of metallic resources does not have iron as a dominating mineral. These constitute the remaining 25% of the metallic minerals. Generally, these resources are relatively better resistant to corrosion.

Characteristics of Metallic Minerals

• Metals in metallic minerals are generally hard and are good conductors of heat and electricity.

• Metallic minerals are the source of metals. 

• Metallic minerals contain compounds of metals generally in the form of their sulphides and oxides. 

• These minerals on extraction give pure metal. 

Non-metallic Minerals 

Non-metallic resources consist of carbon mainly. Coal, petroleum,  natural gas etc. all come under this category and these resources comprise around 87% of all-natural resources production. The rest is shared among metallic resources and non-metallic resources with each gaining around 6 – 7 %.  Non–metallic minerals can be further classified into 2 categories: 

1. Organic Minerals 

2. Inorganic Minerals 

The minerals which have carbon-hydrogen as a part of the compound are termed as organic minerals. Petroleum, coal, natural gas all come under this category. 50% of the world’s coal is mined by China and 10%  is mined by India.

Inorganic resources are those resources which are resources of non-metals but do not have a carbon-hydrogen bond. Mica, graphite, limestone minerals come under this category. 

However the difference between organic and inorganic minerals is not clearly defined and is seen to overlap at certain places.

Characteristics of Non-metallic Resources

• Non–metallic minerals are generally not called ores, instead are called industrial minerals due to their widespread usage in industries to create other substances.

• These resources are lacklustre and can break easily.

• Non-metallic resources generally are not good conductors of heat or electricity.

• These minerals cannot be recycled in a short time duration. 

Uses of Minerals

• Minerals are used in our body in our growth which in turn will help us to stay healthy. Though we need minerals in small quantities but still without them our body growth will be significantly hindered. For example, we need calcium to strengthen our bones and teeth, Zinc helps us to improve our immune system which helps us to remain healthy. Deficiency of iron leads to anaemia.

• Minerals also play an important role in agriculture-based industries as fertilizers and chemicals required in the sector are prepared from different minerals.

• There are many industrial uses of different mineral resources in different ways. For example iron is extensively used in the construction of buildings, developing weapons for defence, Graphite is used in pencils, Potassium is an important part in fertilizer NPK.

• Apart from these minerals are also used in making jewellery. Metals like Gold, Silver, Platinum etc. being valued highly are regarded as valuable metals and hence are sometimes used as a source of hedging funds. These kinds of minerals have the potential for commercial trading.

Conservation of Mineral Resources

• When we consume a mineral resource it’s an irreversible change and hence once consumed, it becomes another chemical compound which is completely different from its parent species.

• Production of mineral resources like coal, petroleum etc. take years and years for production and once consumed, it’s finished forever. 

Above explanation clearly shows that consumption of minerals and production of them is not a cycle but a one-way process towards depletion. Now once we have understood, why do we need to conserve resources? The question is: How do we conserve resources?

Conservation of Resources can be taken Forward in the Following Ways: 

• Reduction in the consumption of resources like petroleum, coal etc which are used in large quantities in various industries and try to find alternatives. For example, coal is widely used in producing electricity but we know that coal plants have very bad efficiency so shift to hydropower, solar power as an alternative is the best choice. This will not only help us to conserve coal but also to conserve our environment. Similarly, instead of petroleum we should try and shift to e- vehicles.

• Minimize the residue or the wastage produced when extracting the metal/s is a step forward towards conservation of the resources.

• 3 R’s ( Recycle, Reduce and Reuse ) will help significantly in conserving these resources. A good example can be recycling of scrap metals. 

• Consumption of metals in better planned and sustained ways is another step towards conservation of resources. Use of public transport whenever possible to save fuel is an example in which better planning will help towards conservation. 

Difference between Metallic and Non-metallic Minerals

There is a major difference between metallic and non-metallic minerals. One of these key differences is that metallic minerals are procured from ores whereas non-metallic minerals are obtained from industrial rocks and minerals. Let’s have a look at some other differences between these two minerals. 

• Metallic minerals are the ones that have metal elements in their raw form. On the other hand, non-metallic minerals do not have any type of metal in them. 

• By melting a metallic mineral, you can obtain a new product. However, non-metallic minerals do not produce any such product when melted. 

• Usually, metallic minerals are obtained from igneous and metamorphic rocks while non-metallic rocks are embedded in sedimentary rocks and young fold mountains. 

• Metallic minerals are known to be good conductors of heat and electricity. On the contrary, non-metallic minerals are good insulators of heat and electricity. 

• Metallic minerals have high ductility and malleability whereas non-metallic minerals lack both malleability and ductility and tend to break quite easily. 

• Metallic minerals usually have a lustre and shine in them. But non-metallic minerals have no such shine or lustre.  

• Copper, tin, iron, and bauxite are some examples of metallic minerals. Salt, mica coal, and clay are common examples of non-metallic minerals.