(i) How does metallic character of an element change as one moves from. (a) Left to right in period ? (b) Top to bottom in group ?

Question

 Given below is the part of Periodic Table:

Li	Be	B	C	N	O	F
Na	Mg	Al	Si	P	s	Cl

(i) How does metallic character of an element change as one moves from. 

(a) Left to right in period ? (b) Top to bottom in group ? 

(ii) How does the valency of elements change with respect to hydrogen as one moves from left to right in period ? 

(iii) (a) What is the valency of element silicon ? 

(b) Will it form a covalent or electrovalent bond with hydrogen ? 

(iv) Which are the most metallic and the most non-metallic elements in above table

Answer 1

(i) (a) As one moves from left to right in period, the metallic character of an element decreases and then it changes to non-metallic character. 

(b) As one moves from top to bottom in period, the metallic character of the elements increases. 

(ii) The valency of elements with respect to hydrogen is stated as under: 

I group +1

II group +2 

III group +3 

IV group -4 

V group -3 

VI group -2 

VII group -1 

(iii) (a) The valency of element silicon is -4 

(b) Silicon will form a covalent compound with hydrogen. 

(iv) Sodium is the most metallic arid chlorine is most non-metallic element.