How many electrons are in the outer energy level of metals nonmetals and metalloids

Each shell can hold only a fixed number of electrons. The first shell can hold up to 2 electrons. the second shell can hold up to 8 (2+6) and the third shell can hold up to 18 (2+6+10) and so on. The general formula is that the nth shell can in principle hold up to 2 (n 2) electrons.