Question

the atomic no. of sodium is 11, fluorine is 9 and neon is 10 why are. sodium and fluorine very reactive while neon shows almost no reactivity

Answer 1

neon don't show any reactivity because the outermost shell of neon is totally filled but the outer most shell of sodium and fluorine contain electron less than 8 they also want to be stable for being stable they shows reactivity

Answer 2

it's because if write the electronic configuration of each elements u will notice that in case of neon....the outermost shell is completely filled....hence it requires very large energy to eject the electrons.....hence it is unreactive....but in the case of sodium and fluorine it is not the case.