Question

Atomic numbers of four elements, A B C D are 5,8,12 B & 17 respectively.

a)Arrange them into increasing order of atomic Size

B) Write molecular formula of compound formed by B&C Also draw it's Electron dot structure. ​

Answer 1

Answer:

Let us take a look at the electronic configurations of the given elements,

A: (2, 7)

B: (2, 8, 1)

C: (2, 8, 7)

D: (2, 8, 2)

E: (2, 8, 3)

We can see that elements A and C both have 7 valence electrons. Thus, both the elements belong to the same group.

So, the correct option is C

Answer 2

Answer:

A,B,C,D are Boron(B), Oxygen(O),

Magnesium (Mg), Chlorine(Cl) respectively, with atomic number 5,8,12,17

a)atomic size in increasing order,

=B<O<Mg<Cl

B+C= O+Mg=MgO( magnesium oxide).