Q: Which one of the following elements is unable to form MF_{6}^{3-} ion?

B is unable to form MF_{6}^{3-} ion.This is because \displaystyle B^{3+} has no vacant d orbitals. It has only on s and 3 p orbitals in the valence shell. Hence, it can accept 4 electron pairs and can form \displaystyle BF_4^- .therefore option A is correct.

Question 1

Which one of the following elements is unable to form  MF_{6}^{3-}  ion?

Accepted Answer

B is unable to form  MF_{6}^{3-}  ion.This is because &#10; \displaystyle B^{3+}  has no vacant d orbitals. It has only on s and&#10; 3 p orbitals in the valence shell. Hence, it can accept 4 electron &#10;pairs and can form  \displaystyle BF_4^- .therefore option A is correct.

Question 2

The element  Z = 114  has been discovered recently. It will belong to which of the following family/ group and electronic configuration?

Accepted Answer

The element  Z=114  has been discovered recently. It will belong to carbon family and its electronic configuration is  \displaystyle [Rn] 5f^{14}  6d^{10} 7s^{2} 7p^{2} . It belongs to seventh period and fourteenth group.Hence, the correct option is  C .

Question 3

Which of the following is a sink for  CO ?

Accepted Answer

Micro organism present in the soil behave as sink for  CO .Hence, option C is correct.

Question 4

The stability of  +1  oxidation state among  Al ,  Ga ,  In  and  Tl  increases in the sequence:

Accepted Answer

The stability of  +1  oxidation state among  Al ,   Ga ,  In  and  Tl  increases in the sequence. \displaystyle Al < Ga < In < Tl  .This is due to inert pair effect due to which, on moving down the group, the stability of  +3  oxidation state decreases while the stability of  +1  oxidation state increases.

Some P-Block Elements