Question

Potassium and oxygen will combine to make a compound.

K_O_


Fill in the blanks with the number of the subscript.

Answer 1

Look at your periodic table and notice that potassium appears in the first column. This means it has 1 electron in its outer shell.

Now look again at your periodic table and see that oxygen appears near the right side, in the third column from the right. The elements of the rightmost column, the noble gases, all have 8 electrons in their outer shell, which fills it completely. Oxygen, being two columns to the left of that column, has 6 electrons in its outer shell. This means oxygen would prefer to find an atom or two of a metal that it could hold close to use that metal's one or two outer shell electrons to have a full set of 8.

If oxygen has 6, and potassium has 1, how many potassium atoms need to bond with an oxygen atom to make the whole group have a full shell of 8?