Ionic Bonding

Now you know how to identify the charges, we shall talk about ionic bonding. Ionic bonding is the bonding of Metals and Non-metals via the giving and taking of electrons.

Let's start off with something simple.
eg.
Potassium has a 1 electron in its outermost shell as it is in group I of the periodic table. and needs to give away one electron to fulfil the octet configuration. Thus it has a charge of (+1).
Iodine has 7 electrons in its outermost shall as it is in group VII of the periodic table and needs to take in one more electron to fulfil the octet configuration. Thus it has a charge of (-1).
When ionic bonding occurs, the main purpose is to make the positive and negative charge equal so. Thus, to make the charges of the two elements equal, we need one of each element.

Therefore, Potassium and Iodine will react to form KI, potassium iodide by ionic bonding.

Calcium + Chlorine?

Calcium has a charge of 2+
Chlorine has a charge of 1-

How to balance? To make the negative charge = positive, we need two chlorine atoms right? bingo.

So it forms CaCl*2, calcium chloride

* represents subscript

Got it? Yay. xD

try others.
Magnesium + Oxygen? ans: MgO
Aluminium + Oxygen? ans: Al*2O*3
Sodium + Chloride? ans: NaCl
Calcium + Chloride? ans: CaCl*2
Zinc (II) + Oxygen? ans: ZnO
Iron (III) + Oxygen? ans: Fe*2O*3
Silicon (IV) + Oxygen? ans: SiO*2