[Chemistry Class Notes] Ion Pdf for Exam

You have been hearing since childhood that there are ions in our body, where some are positive and some negative. Positively charged ions are called cations, while a negative ion is known as an anion. 

An ion is an atom or a molecule that carries some charge either by losing or gaining an electron.

If we name the ions which are positively charged, then we have the following list:

1. K+

2. Na+

3. Ca2+

4. Mg2+

Negative ions are Cl–, O2-, S2-, Br–, etc.

This page will help you understand what is an ion with its types and the ion formation.

What Do You Mean by Ions?

Do you know what does ion mean and what type of ion forms when an atom loses electrons or what happens when an atom gains an electron?

An ion is a particle that possesses an electrical charge. It becomes a cation on losing an electron and becomes an anion when it gains an electron. Also, the negative charge or an electron an atom holds is always equal and opposite to the positive charge or protons of an atom.

What is a Charged Atom Called?

A charged atom is called an ion and what are ionic compounds made of; let’s understand this in detail:

What is an Ionic Compound? 

From the above text, we understood what an ion is in Chemistry. Now, we will understand what is an ionic compound. 

In Chemistry, we call ionic compounds chemical compounds that are formed of two or more ions held together by an electrostatic force of attraction; these electrostatic forces form bonds called ionic bonds. Here, these ionic bonds are formed between positively charged ions called cations and negatively charged ions called anions.

So, what is a cation? 

What is a Cation?

Now, Let’s Understand what is a Cation with a Real-Life Example:

What do you find common among the battery, your heart, and fertile soil? The answer to this question is, it requires cations to work.

However, let’s think more specifically. Have you ever gulped down a protein shake after becoming dehydrated from vigorous physical activity? Maybe a trainer, your coach, gym teacher, or even a sports drink commercial might have told you that consuming the beverage would help you replace your electrolytes. An electrolyte is a solution that contains ions and in drinking the sports drink, you consume cations. But what is a cation?              

A cation is a positively charged ion that gets attracted towards the cathode in electrolysis. As you know that an atom is electrically neutral. This is because the number of protons equals the number of electrons in an atom and the charges balance out. When an atom loses one or more electrons,  it now has more protons, or positively charged particles, than electrons, or negatively charged particles.

What Type of Ion Forms When An Atom Loses Electrons?

For example, when atoms like Na, Ca, Mg, K loses electrons, it becomes positively charged by losing electrons accordingly:                                  

In the above, we can see that atoms on losing electron (s) become positively charged; however, the number of protons before and after the ion formation remains the same.

What is an Anion?

An anion carries a negative charge that gets attracted towards the anode in electrolysis. All non-metals gain two or more electrons and do not lose any proton. Therefore, these elements possess a net negative charge. Some examples of anions are Iodide ion (I– ), chlorine (Cl– ), hydroxide (OH–).

Point To Ponder:

A trick to remember to distinguish between a cation and an anion is to say to yourself the following:

Cation –  ‘I positively love cats!’, and

Anion –  ‘I get annoyed with negative people.’

What Type of Ion Forms When an Atom Gains Electrons?

In the above table, we can see that non-metals like Cl, F, O, N when gains electron (s) becomes negatively charged or an anion with the increase in the number of electrons; however, the number of protons before and after the ion formation remains the same.