1. Chemical Bonding
FAQs

2. Chemical Bonding
1. How do we calculate formal charge?
1. Break the bonds in the molecule.
2. Split the electrons equally between the atoms
in each bond
3. FC = no. e gain/lost

3. Chemical Bonding
1. How do we calculate formal charge?
Example:

4. Chemical Bonding
1. How do we calculate formal charge?
Formal charges are incurred when:
1. there are dative bonds
2. atom gains/ loses electrons

5. Chemical Bonding
2. How do we calculate bond order?
1. Bond order represents the number of covalent
bonds between 2 atoms.
It is usually an integer unless delocalisation of
pi bonds are possible.

6. Chemical Bonding
2. How do we calculate bond order?
Example: SO42–
Due to delocalisation of pi bonds in the ion, there are 1.5
bonds between each S and O atom.

7. Chemical Bonding
3. How does bond order relate to bond length?
• Bond order represents the number of covalent bonds
between 2 atoms.
• The greater the no. of bonds between 2 atoms, the
stronger the bond, the shorter the bond length.

8. Chemical Bonding
4. Is a lone electron considered an electron
domain i.e. lone pair?
• Yes. The lone electron is consider as a lone pair
when assigning shape.
• Example: NO2 [2 bp, 1 lp] V shaped

9. Chemical Bonding
5. When do we use double bond or dative bond?
• In drawing Lewis structures, double bonds are
preferred since they do not incur formal charge.
• Dative bonds are used when the central atom cannot
expand beyond octet.

10. Chemical Bonding
6. How do we determine if a molecule is polar?
1. Look at the bonds in the molecule; are the polar (i.e.
do the atoms have different electronegativities?)
Example:
C–H bond non polar
C–Cl bond polar

11. Chemical Bonding
6. How do we determine if a molecule is polar?
2. If the molecule consists of polar bonds, determine if
the dipoles cancel out.
Example: