THE PERIODIC TABLE

4.7 - Covalent Bonding

4.7.1 - Covalent Bonds and Groups

The location of an element in the periodic table allows us to predict the number of covalent bonds that it can form.

1. Hydrogen belonging to Group IA has one valence electron, shares this valence electron with another atom to form one covalent bond.
2. Boron belonging to Group IIIA has three valence electrons, shares its valence electrons with other atoms to form three covalent bonds.
3. Carbon and Silicon belonging to Group IVA have four valence electrons, shares their valence electrons with other atoms to form four covalent bonds.
4. Nitrogen and Phosphorus belonging to Group VA has five valence electrons, shares three of its five valence electrons with other atoms to form three covalent bonds. The other two valence electrons form one nonbonding electron pair.
5. Oxygen and Sulfur belonging to Group VIA has six valence electrons. These elements need two valence electrons to complete an octet of electrons. They share two of the six valence electrons with other atoms to form two covalent bonds. The other four valence electrons form two nonbonding electron pair.
6. Fluorine, Chlorine, Bromine and Iodine belonging to Group VIIA has seven valence electrons. These elements need one valence electron to complete an octet of electrons. They share one of the seven valence electrons with other atoms to form one covalent bond. The other six valence electrons form three nonbonding electron pair.

Section 6.5
The Covalent Bond ..p128

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