Question

Among BF3, NF3, PH3, IF3, IFs and SF4, the number of
species having the same number of lone pair of electrons on
the central atom is​

Answer 1

Answer:

NF3, PH3, IF5 , SF4 will have one lone pair.

BF3 will have no lone pair.

IF3 will have 2 lone pairs.

Answer 2

$NF_3, PH_3, IF_5$ and $SF_4$ have the same number of lone pair of electron on central atom.

Explanation:

For finding the number of lone pairs on the central atom, we can find the number of valence electrons of the atom and then the number of electrons involved in bonding. The remaining electrons are the lone pairs.

In $BF_3$, B has 3 valence electrons, and all involved in bonding, so no lone pairs.

In $NF_3$, N has 5 valence electrons, of which 3 are involved in bonding, so 2 electrons are present as lone pair on N.

In $PH_3$, P has 5 valence electrons, of which 3 are involved in bonding, so 2 electrons are present as a lone pair on P.

In $IF_3$, I has 7 valence electrons, of which 3 are involved in bonding, so 4 electrons are present as 2 lone pairs on I.

In $IF_5$, I has 7 valence electrons, of which 5 are involved in bonding, so 2 electrons are present as a lone pair on I.

In $SF_4$, S has 6 valence electrons, of which 4 are involved in bonding, so 2 electrons are present as a lone pair on S.

Thus, $NF_3, PH_3, IF_5$ and $SF_4$ have one lone pair on central atom each.