GEN. CHEM Q from DAT DESTROYER

[biostudent101]

Q314. how many lone electron pairs are found in AsBr3? the solution manual says 10 lone electron pairs. I don't understand where he got 10 from?

Thanks

 

[Dentite99]

Q314. how many lone electron pairs are found in AsBr3? the solution manual says 10 lone electron pairs. I don't understand where he got 10 from?

Thanks

Try to draw it out:

As has 5 total e-, sharing three , Br has 7 valence, sharing one.
Put 3 Br's around the central As and add up the pairs= 10 e- pairs.

 

[nze82]

As = Group 5

Br = Group 7

5 + 3(7) = 26

Three bonds connect Br to the central As atom, so:

26 - 3(2) = 20 --># of lone pairs

Now distribute these 20 electrons around the Br and then As atoms:

How many pairs of red dots do you see?
10

 

[biostudent101]

thanks. i got it.