How do you write the formula for calcium fluoride?

1 Answer
Jan 12, 2016

The formula for calcium fluoride is CaF2.

Explanation:

An ionic compound is neutral, which means its overall charge is zero. Therefore, the sum of the charges of each ion in the compound must equal zero.

In calcium fluoride, the calcium ion Ca2+, has a charge of 2+, and the fluoride ion F1 has a charge of 1. We will need two fluoride ions to make the overall charge zero.

Ca2++ 2F1CaF2

There is a method that makes it fairly easy to determine the formula unit of an ionic compound. It's called the crisscross method. In the crisscross method, the size of the charge of each ion becomes the subscript of the other ion.

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