Page 53 - Chemistry_Form_2

Chemistry
for Secondary Schools

FOR ONLINE READING ONLY

Figure 3.1: Bricks bonded using mortar to form a wall

A chemical bond is a force of attraction that holds atoms or ions together to form
molecules or compounds. The bond may result from forces of attraction between
oppositely charged ions or through the sharing of electrons.

Note: A molecule is the smallest particle of an element or compound which can
normally exist separately.

Chemical bonding

Chemical bonding involves electrons in the outermost shells of atoms. When the
outermost shells are completely filled with electrons, the atoms are said to be
stable, otherwise they are unstable. Table 3.1 shows the electronic arrangements
of some elements and the stability of atoms of the elements. From Table 3.1,
only helium, neon, and argon have stable electronic arrangements. Helium has a
maximum number of 2 electrons in its outermost shell. Neon and argon have a
maximum of 8 electrons in each of their respective outermost shells. These stable
atoms are generally unreactive and can exist freely as single atoms. Unstable
atoms cannot exist freely as single atoms. For unstable atoms to become stable,

they should acquire electronic arrangements similar to those of noble gases. This
means that they can either lose, gain or share electrons through chemical bonding.

46 Student’s Book Form Two

CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 46 01/08/2025 11:20:54
01/08/2025 11:20:54
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 46