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Grade 12Physical Chemistry

How to find the number of lone pairs and bon d pairs in the central atom of NH3 molecule??? I will approve the ans for sure..aieee-givin me the creeps pls reply soon

Profile image of Geoffrey Richards
15 Years agoGrade 12
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2 Answers

Profile image of vikas askiitian expert
ApprovedApproved Tutor Answer15 Years ago

number of valence electrons are 5 ...

3 electrons take part in bonding so 2 are remaining ..

lone paires  = 1

bond paires = 3 (total number of bonds)

Profile image of Sudheesh Singanamalla
ApprovedApproved Tutor Answer15 Years ago

1. First know the electronic configuration of N and H

2. We know Nitrogen has 5 valance electrons and H has 1 valance electron.

in NH3 , 3 of the 5 valance electrons on N are taken by 'H' , so it has 2 electrons left.

3. These 2 electrons will prevent it from acquiring a trigonal planar shape as they will repel the bonding.

we know this because , according to VSEPR theory , the bonds should be in such a position such that the repulsions between them is very less.

so NH3 gets a tetrahedral shape, with a lone pair of electrons.

so the final sctructure will look like ..

351_16302_ammonia.jpg

Please approve !