An element A reacts with oxygen to form A_2 O. (i) State the number of electrons in the outermost orbit of A. (ii) To which group of the periodic table does A belong? (iii) State whether A is a metal or a non-metal.

An element A reacts with oxygen to form A_2 O. (i) State the number o

1.	An element A reacts with oxygen to form A_2 O. (i) State the number of electrons in the outermost orbit of A. (ii) To which group of the periodic table does A belong? (iii) State whether A is a metal or a non-metal.
Answer» Solution :(i) As the valency of oxygen is 2, the valency of A must be 1 in ORDER to obtain the compound `A_2 O` . Therefore, the number of ELECTRONS in the outermost orbit of A is 1. (ii) A BELONGS to Group 1 of the PERIODIC Table. Elements of this group have 1 ELECTRON in the outermost orbit. (iii) A is a metal. Elements of Group 1 having 1 electron in the outermost orbit have a tendency to lose electrons.