Question

In the elements of the third period: Na, Mg, Al, Si, P, S, Cl, and Ar, Choose non-metals

Answer 1

• Metals are electron donors, they generally have 1,2 or 3 electrons In their outermost shell.
• Similarly non-metals are electron acceptors, they generally have 5,6 or 7 electrons in their outermost shell. And semi-metals on the other hand generally have 4 electrons in their valence shell.
• Electronic configuration for set of elements given in the question is

$$\begin{gathered} {}_{11}Na\to 2,8,1 \\ {}_{12}Mg\to 2,8,2 \\ {}_{13}Al\to 2,8,3 \\ {}_{14}Si\to 2,8,4 \\ {}_{15}P\to 2,8,5 \\ {}_{16}S\to 2,8,6 \\ {}_{17}Cl\to 2,8,7 \end{gathered}$$.

• Hence, Phosphorus (P), Sulphur (S) and Chlorine (Cl) has 5, 6 and 7 valance electrons in their outermost shell respectively, so they will tend to accept electrons, so they are non-metals.