Question

Four elements A,B,C and D have atomic numbers 12,13,14 and 15
respectively.Answer the following questions with reasons.
a) Which elements form covalent bond?
b) Arrange the elements in the increasing order of their atomic size.
c) Which is more metallic and which is more non-metallic?
d)To which period all these elements belong?
e)Write the formula of the oxide of element A and chloride of
element B.​

Answer 1

Answer:

d) 3rd period  and (e)oxide of A is MgO and chloride of B is AlCl3

Explanation:

d)all these elements belong to 3rd period.As,all these have atomic no. more than 10(2nd period) so they must belong to a period above than that.

Answer 2

Answer:

a) atm no 12- Mg

Mg forms polar covalent bond which is very close to ionic bond. For Eg : in grignard reagent Mg-C bond is polar covalent and electronegativity diffrence is 1.24

b) 15- P < 14- Si < 13- Al < 12- Mg

c) 12- Mg is more metallic than other & 15-phosphorus is more non-metallic character than other

d) All these elements belong to Third grp

e) element A's oxide ====>MgO

element B's chloride ==>AlCl3