Nan atom, the first energy level can hold electrons. the second energy level can hold electrons. the third energy level can hold electrons.

Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, 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(n2) electrons.

a chemical reaction happens

explanation:

i just learnt this recently but i need to look through my notes again