Question

How to find a substance is metal or non metal by knowing its valu in valent shell

Answer 1

by knowing the value of valent shell we can find that if the element can lose or gain the electrons easily.If it can lose electrons for ex- in case of sodium there are 1 electron in it's valent shell hence it become easy for it to lose the electron therefore , it is a metal .Whereas , when the element can gain the electron easily for e.g chlorine have 7 electrons in it's valence shell therefore it become easy for the chlorine to gain an electron to become balance hence it is non - metal..
hope I answered satisfactorily .....