Question

What is ionic size in chemistry?

Answer 1

The ionic size is when the atom loses or gains electrons to become negatively charged (anions) or positively charged (cations) ions.

Explanation:

The ionic size is when the atom loses or gains electrons to become negatively charged (anions) or positively charged (cations) ions. When atoms lose or gain electrons, the size of the ion is not the same as the original atom.

Metal atoms generally lose their valence electrons to form positive ions called cations. This is because electrons have a negative charge and protons have a positive charge and when the metals lose their electrons, they become positively charged because there are now more protons in the atom than electrons.

For example:
Sodium atom: 11 electrons and 11 protons.
Sodium ion (Na+): 10 electrons and 11 protons.

Magnesium atom: 12 electrons and 12 protons.
Magnesium ion (Mg2+): 10 electrons and 12 protons.

As for non-metal atoms, they generally gain their valence electrons to form negative ions called cations. This is because electrons have a negative charge and protons have a positive charge and when the non-metals gain their electrons, they become negatively charged because there are now more electrons in the atom than protons.

For example:
Chlorine atom: 17 protons and 17 electrons.
Chlorine ion (Cl-) : 17 protons and 18 electons.

Oxygen atom: 16 protons and 16 electrons.
Oxygen ion (O2-): 16 protons and 18 electrons.

This, therefore, fills up their outer shell so that they can become complete.