Chemical Formulas for Ionic compounds

COMPOUNDS

5.8 - Chemical Formulas for Ionic compounds

Write the chemical formula involving calcium and nitrogen

Here we look at the charges on the ions.

calcium	+2
nitrogen	-3

Drop the signs on the charges and determine the lowest common multiple (LCM) between "2" and "3".

For Ca⁺² and N^-3, the LCM is

2 x 3 = 6

To determine the number of ions needed,

LCM / charge of ion = number of ions

Step 2:

Number of Ca⁺² ions		Number of N^-3 ions
6/2 = 3 Ca⁺² ions		6/3 = 2 N^-3 ions

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