Question

How many groups and periods are there in periodic table If two elements X and Y belong to group 1 and 2 in the same period of periodic table Then compare that from two groups 1 the valency of their oxides.2 then molecular formula of their oxides

Answer 1

There are 7 period and 18 groups in the modern periodic table.

(i) it depend on the element that how much valency it has.

Group 1.

(a) X2O-----> this is oxide of X

because X has valency 1 and O is

2.

(b) YO------> this is oxide of Y because

Y has valency 2 and O is 2.

(ii) Molecular formula of there oxides

are

(a) X+O--------->X2O

(b) Y+O-------->YO