Na, Mg, Al, Si, P, S, Cl and Ar are elements of 3rd period which of them is inert and why

Na, Mg, Al, Si, P, S, Cl and Ar are elements of 3rd period which of th

1.	Na, Mg, Al, Si, P, S, Cl and Ar are elements of 3rd period which of them is inert and why
Answer» Argon is INERT GAS because the OUTERMOST SHELL is fully complete...