Question

One of two binary ionic compounds is often added to toothpaste. One of these compounds contains sodium and fluorine; the other contains tin(II) ions and fluorine.

Write the formula for the compound that contains sodium and fluorine.
a) NaF
b) Na₂F
c) NaF₂
d) Na₂F₃

Answer 1

The compound containing sodium and fluorine that is commonly added to toothpaste is sodium fluoride, with the chemical formula NaF.

Step-by-step explanation:

The formula for the compound that contains sodium and fluorine, which is often added to toothpaste, is NaF, otherwise known as sodium fluoride. Sodium ions (Na+) have a +1 charge and fluoride ions (F-) have a -1 charge. When these two ions combine in a binary ionic compound, they do so in a one-to-one ratio to create a compound with a neutral overall charge, thus the formula NaF. This stands in contrast to other ionic compounds that may require multiple ions to balance the charges, as seen with calcium fluoride which has a formula of CaF2.