Explain the ratio of calcium ions to chloride ions in CaCl2

The ionic formula for Calcium Chloride is

C

a

C

l

2

Calcium is an Alkaline Earth Metal in the second column of the periodic table. This means that calcium has 2 valence electrons it readily gives away in order to seek the stability of the octet. This makes calcium a

C

a

+

2

cation.

Chlorine is a Halogen in the 17th column or

p

5

group.

Chlorine has 7 valence electrons. It needs one electron to make it stable at 8 electrons in its valence shells. This makes chlorine a

C

l

−

1

anion.

Ionic bonds form when the charges between the metal cation and non-metal anion are equal and opposite. This means that two

C

l

−

1

anions will balance with one

C

a

+

2

cation.

This makes the formula for calcium chloride,

C

a

C

l

2

.

I hope this is helpful.

yes 2.5 is correct for plato!