Based on the group valency of elements state the formula for the following giving justification for each: i] Oxides of Ist group elements, ii] Halides of the elements of group 13, and iii] Compounds formed when an element of group 2 combines with elements of group 16 .

Based on the group valency of elements state the formula for the follo

1.	Based on the group valency of elements state the formula for the following giving justification for each: i] Oxides of Ist group elements, ii] Halides of the elements of group 13, and iii] Compounds formed when an element of group 2 combines with elements of group 16 .
Answer» Solution :i] First-group elements have a VALENCY +1 and oxygen has valency-2. Hence, their OXIDES have the FORMULA `M_2O` ii] Group 13 elements have valency +3 and CHLORINE has valency -1. Hence, their halides have formula `MCI_3` iii) Elements of group 2 have a valency +2 while elements of group 16 have a valency -2. Hence, their COMPOUNDS have the formula MX.