Page 60 - Chemistry_Form_2

Chemistry
for Secondary Schools

FOR ONLINE READING ONLY

Hydrogen atom Chlorine atom Hydrogen chloride molecule

or H – Cl or HCl
Figure 3.6: Sharing of electrons in a hydrogen chloride molecule

The same happens to the combination between oxygen and hydrogen. Oxygen
requires two electrons to acquire a stable structure, while hydrogen requires one
electron. Thus, one oxygen atom combines with two hydrogen atoms as shown
in Figure 3.7, whereby each hydrogen provides one electron for sharing with
oxygen (any pair from the outermost shell).

Outermost shell
with paired
electrons

8p 8p
8n 8n

Two hydrogen atoms Oxgen atom Water molecule
or

or H–O–H or H O
2
Figure 3.7: Covalent bonding in a water molecule

Covalent bonds are usually formed between non-metals. Molecules of covalent
compounds are discrete or distinct. This means that the atoms forming the
molecules cannot exist freely in the compounds. They remain bound together in
molecules and their electrons are not free to form bonds with other atoms.

Student’s Book Form Two 53

01/08/2025 11:20:55
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 53 01/08/2025 11:20:55
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 53