How many electrons must be lost by an atom of calcium for it

How many electrons must be lost by an atom of calcium for it to obtain a stable electron configuration? 1 2 3 4 5 6 7 8

Solution

The correct answer is 3 The atomic number of Nitrogen is 7. So the inner s orbital is occupied with 2 electrons and the outer p has occupied with 5 electrons. Therefore in order to complete its octet configuratiin, 3 more electrons will be required so as to complete 8 electrons in the outermost shell.