Classify the elements of the third period into metals and non-metals.

Explanation

The elements in the third period are Sodium (Na), Magnesium (Mg), Aluminium (AI), Silicon (Si), phosphorus (P), Sulphur (S), Chlorine (CI) and Argon (Ar). Out of these elements, Sodium (Na), Magnesium (Mg) and Aluminium (Al) which are to the left of the periodic table are metals and phosphorus (P), Sulphur (S) and Chlorine (Cl) which are to the right of the periodic table are nonmetals.