When oxygen combines with any alkali metal, M, what is the formula of the compound produced usually?
The basic formula is
To answer this, we can take a look at the ionic charges of the elements involved.
Since oxygen is in group 16, it will have
Recall that an atom will want to gain or lose electrons to fulfill the octet rule; it wants to do whatever is easiest to obtain
For an oxygen atom, the easiest way to get
For the alkali metals, which are located in group 1 of the periodic table, they each have
In order to obtain an octet for each of the alkali metals, the easiest way to do it is by removing its one valence electron. This will cause each of the atoms (symbol
The compound the alkali metal
The easiest way to write a formula of any ionic compound if you know the ionic charges of each species is to put the charge of the anion (the negative ion, in this case is