Page 56 - Chemistry_Form_2

Chemistry
for Secondary Schools

Na Cl

FOR ONLINE READING ONLY

Na + Cl –

or NaCl

Figure 3.3: Electrovalent bonding in sodium chloride
Molecules of electrovalent compounds are not discrete. This means that the
electrons are not localised or attached to particular ions of opposite charges to
form pairs. Instead, a group of cations surround an anion and a group of anions
surround a cation. This means that ions can move freely around each other,
especially when in molten or in solution forms.

Properties of electrovalent compounds
Electrovalent (ionic) compounds have the following properties:

(a) They are generally soluble in water.

(b) They conduct electricity in solution or molten forms but not in their solid
forms.
(c) They are usually crystalline solids at room temperature.

(d) They have high melting and boiling points.

Student’s Book Form Two 49

01/08/2025 11:20:54
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 49 01/08/2025 11:20:54
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 49