Ionic radius

Imagine you are trying to stack different sizes of balls on top of each other. Some balls might be really big and others might be really small. When you stack them, you might notice that some combinations work better than others.

In a similar way, atoms are like balls and they come in different sizes. The size of an atom is called its atomic radius. But when you put atoms together to form a molecule, their atomic radius can change slightly. This is where ionic radius comes in.

When atoms form ions (which are charged particles), the size of their atomic radius can change. This is because ions can have either a positive or negative charge, and the number of electrons they have can change. As a result, the distance between the nucleus (the center of an atom) and the electrons changes, which affects the overall size of the ion.

For example, if we compare the size of a sodium atom to the size of a sodium ion, we would find that the sodium ion is smaller than the sodium atom. This is because when sodium loses an electron to become a positively charged ion, the remaining electrons are pulled closer to the positively charged nucleus, making the ion smaller.

In summary, ionic radius refers to the size of an ion, which can change depending on the number of electrons it has and the type of charge it carries. It's like stacking balls of different sizes – some combinations work better than others depending on the size of the balls.