# What is the chemical name for "Na"_2"O" ?

Mar 24, 2018

Sodium oxide.

#### Explanation:

The first thing to notice here is that this compound contains a metal, sodium, and a nonmetal, oxygen, so right from the start, you know that you're dealing with an ionic compound.

Now, sodium is located in group 1 of the Periodic Table, which means that an atom of sodium has $1$ valence electron. In order to complete its octet, sodium will lose this valence electron and form the sodium cation, ${\text{Na}}^{+}$.

Oxygen, on the other hand, is located in group 16 of the Periodic Table, which means that an atom of oxygen has $6$ valence electrons. In order to complete its octet, oxygen takes in $2$ electrons and forms the oxide anion, ${\text{O}}^{2 -}$.

In order to name this compound, use the name of the cation first and the name of the anion last.

You will have

"Na"_ 2"O" -> 2color(blue)(["Na"]^(+)) + color(red)(["O"]^(2-)) -> color(blue)("sodium") quad color(red)("oxide")

Notice that the sodium cation carries a $1 +$ charge and the oxide anion carries a $2 -$ charge, which is why you need $2$ sodium cations to balance the overall negative charge coming from $1$ oxide anion.