Scientists, Professionals, Teachers, and Students of Chemistry widely use the periodic table of elements to search for chemical elements. Dimitri Mendeleev is referred to as the Father of the periodic table put forth the first form of the Periodic Table. This periodic table was based on the atomic mass of the elements. During his time only half of the elements known to us now were known, and not all of the information about elements was fully known or accurate. The latest Periodic Table is based on Henry Moseley’s modern periodic law (Henry Moseley is an English physicist). As per the periodic law, the properties of Elements are periodic functions of their atomic numbers. The Periodic Table is made up of 118 Elements.
Key Characteristics of the Periodic Table:
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Elements are arranged in order of increasing atomic number.
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Elements of the Periodic Table are denoted by a unique symbol and not its entire name, as some elements’ names can be long and complex in nature.
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Elements are arranged vertically and horizontally. Elements arranged vertically in columns are called ‘Groups’ and elements arranged horizontally in rows are called ‘Periods’.
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Further elements are grouped as per periodic trends and properties. Example: Elements in group 1A are soft metals that react violently with water.
Symbol of an Element
A symbol representing a chemical element is a ‘sign’ or ‘notation’ that generally consists of one or two letters. Some symbols have three letters, they generally represent synthesized elements newly, with some being temporarily named like that.
Symbols and How They are Derived?
One may ask, ‘How is the symbol of an element derived?’ We can see in the table above that most of the symbols are derived from the elements’ names, by taking either the first or first two letters from the English name of the element.
Some symbols of a few elements are derived from their Latin or Greek names. Let us look at some examples:
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The Latin name for gold is Aurum. Hence gold is denoted by the symbol ‘Au’.
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The symbol ‘Fe’ is used to denote Iron, as the Latin word for Iron is “Ferrum”.
Rules or Conventions followed to denote the Element using Symbol
The first letter of a symbol is capitalized with the second (or third) letters being in lowercase. Example: ‘Ca’ representing Calcium, ‘He’ representing Helium, etc. When the symbol representing an element is denoted by one letter only, it is written in uppercase.
Example: ‘N’ represents Nitrogen, ‘O’ represents oxygen, etc.
The elements which are new are temporarily named according to their atomic numbers. For example, the element with atomic number 110 was named as ‘un un nilium’ with the symbol ‘Uun’, now it is named Ds.
As far as students are concerned, it is important to study all the 118 elements with their Symbol and Valency. Chemical formulas and equations are also represented using those symbols. Without the symbols, it would have been a herculean task to represent all these 118 elements and the umpteen numbers of compounds they form.
Valency of an Element
In order to achieve the most stable configuration i.e. of a noble gas, the atom of an element tries to gain or lose electrons. This ability of an atom to gain or lose electrons to achieve a stable configuration or inert gas configuration is called the Valency of an element. The number of electrons in the outermost shell is called valence electrons and the outermost shell is called the valence shell. The valency of an element is determined by the number of electrons in the valence shell. It is important to know the atomic number and electronic configuration of an element to find its valency.
Atomic Number
The concept of atomic number and Valency can only be understood if you know what exactly elements are made up of. An element is made up of a single type of atom. An atom is the smallest indivisible unit of matter. It consists of electrons, protons and neutrons. The centre of the atom is also called the nucleus which is positively charged and consists of protons and neutrons. Protons are positively charged. Neutrons are neutral so that it doesn’t have any charge on them. The nucleus is surrounded by negatively charged electrons.
The sum of protons and neutrons gives the atomic mass of an element. The atomic number is the total number of protons present in the nucleus of an atom. It is denoted by the letter Z. The chemical properties of an element are determined by the number of protons in the nucleus. This is why the knowledge of atomic numbers is important in understanding the chemistry of elements.
The following table gives the list of 118 elements along with their symbols and atomic number.
Table of 118 Elements – Their Symbols and Atomic Number
Conclusion
Out of all the 118 Elements, 98 Elements are found in nature (those with atomic number 1- Hydrogen ‘H’ to atomic number 98 – Californium ‘Cf’; in the periodic table), with the rest being synthesized from the naturally occurring elements, in a laboratory. Elements synthesized in the laboratory include Einsteinium (99), Fermium (99) and Nobelium (102). However, this figure can change with time and better understanding, as some elements found after radioactive decay after nuclear testing experiments, therefore considered initially to be man-made, have subsequently been found in nature albeit in trace quantities.
Also, out of the many elements occurring in nature not all of them occur in pure or native form. Noble gases like Helium, Argon, Neon, etc., are a few elements occurring in pure form. Metals like Gold, Silver, Copper, occur in their native form. Non-metals like carbon, nitrogen and oxygen occur in native form. Alkali metals and rare earth elements occur naturally although not in their native form.