Question

1. Fill in the table below for the following compounds- molecules and polyatomic ions. For each compound, calculate the number of available electrons for all the atoms in the molecule and determine what the central atom in the molecule will be. Central Atom Total Number Molecular of Available Formula Electrons HCN P1 P2 SO3 P3 P4 NO3 P5 P6 P7 P8 SIH4 P9 P10 SO2CI2 NH4 P11 P12 P13 P14 PO43 P15 P16 PF5 SF&C P18 P17 P19 P20 XeF2

Answer 1

Total number of electrons available is found by adding the valence electrons of each atom in the given compound.

1) HCN

Total number of electrons = 10

1 from H, 4 from C and 5 from N

central atom= C

2)SO3

Total number of electrons= 24( 6 from S and 18 from 3 O)

Central atom= O

3) NO3^-

Total electrons = 5+6*3 +1 = 24( +1 because an electron is added to the molecule. It is represented as NO3-)

central atom= N

4) SiH4

Total electrons= 4+4= 8

central atom= Si

5) SO2Cl2

Total electrons= 6+12+ 7*2= 32

central atom= S

6) NH4+

Total electrons = 5+4-1= 8

central atom=N

7)PO4-3

Total electrons= 5+ 4*6+3= 32

Central atom = P

8)PF5

Total electrons = 5+ 7*5=40

Central atom= P

9)SF5Cl

Total electrons= 6+7*5+7=48

central Atom= S

10)XeF2

Total electrons= 8+7*2=22

Central atom= Xe