Question

The species which contains highest number of non-
bonding electrons is
(1) CIF3 (2) XeF4 (3) PCl5 (4) XeO3​

Answer 1

Answer:

Lone pair is a concept used in valence shell electron pair repulsion theory (VSEPR theory) which explains the shapes of molecules. They are also referred to in the chemistry of Lewis acids and bases. However, not all non-bonding pairs of electrons are considered by chemists to be lone pairs. Examples are the transition metals where the non-bonding pairs do not influence molecular geometry and are said to be stereochemically inactive. In molecular orbital theory (fully delocalized canonical orbitals or localized in some form), the concept of a lone pair is less distinct, as the correspondence between an orbital and components of a Lewis structure is often not straightforward. Nevertheless, occupied non-bonding orbitals (or orbitals of mostly nonbonding character) are frequently identified as lone pairs.

Lone pairs in ammonia (A), water (B), and hydrogen chloride (C)

I hope it's help to you

Answer 2

Answer :  The correct option is, (3) $PCl_5$

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

Now we have to determine the number of non-bonding electrons in the following molecules.

(1) The given molecule is, $ClF_3$

As we know that chlorine and fluorine have '7' valence electrons.

Therefore, the total number of valence electrons in $ClF_3$ = 7 + 3(7) = 28

According to Lewis-dot structure, there are 6 number of bonding electrons and 22 number of non-bonding electrons.

(2) The given molecule is, $XeF_4$

As we know that xenon has '8' valence electrons and fluorine has '7' valence electrons.

Therefore, the total number of valence electrons in $XeF_4$ = 8 + 4(7) = 36

According to Lewis-dot structure, there are 8 number of bonding electrons and 28 number of non-bonding electrons.

(3) The given molecule is, $PCl_5$

As we know that phosphorus has '5' valence electrons and chlorine has '7' valence electrons.

Therefore, the total number of valence electrons in $PCl_5$ = 5 + 5(7) = 40

According to Lewis-dot structure, there are 10 number of bonding electrons and 30 number of non-bonding electrons.

(4) The given molecule is, $XeO_3$

As we know that xenon has '8' valence electrons and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in $XeO_3$ = 8 + 3(6) = 26

According to Lewis-dot structure, there are 12 number of bonding electrons and 14 number of non-bonding electrons.

From this we conclude that, $PCl_5$ species contains highest number of non-bonding electrons.

Hence, the correct option is (3) $PCl_5$