(a) Name first three members of Group 2 and 16. (b) Name any four metalloids. (c)' Which chemical properties were stressed by Mendeleev while formulating his Periodic Table? (d) Write the following elements in order of increasing atomic numbers : Magnesium, Lithium, Aluminium. (e) Give the electronic configuration of the following elements: Carbon, Phosphorus, Chlorine.

(a) Name first three members of Group 2 and 16. (b) Name any four met

1.	(a) Name first three members of Group 2 and 16. (b) Name any four metalloids. (c)' Which chemical properties were stressed by Mendeleev while formulating his Periodic Table? (d) Write the following elements in order of increasing atomic numbers : Magnesium, Lithium, Aluminium. (e) Give the electronic configuration of the following elements: Carbon, Phosphorus, Chlorine.
Answer» Solution :(a) First THREE MEMBERS of Group 2 are Be, Mg and CA. First three members of Group 16 are 0, S and Se. (b) Boron, silicon, germanium and arsenic are metalloids. (c) Formulae of hydrides and oxides formed by the elements. (d) Lithium `lt` MAGNESIUM `lt` Aluminium (e) `{:("Carbon:",2","4),("Phosphorus:",2","8","5),("Chlorine:",2","8","7):}`