Page 55 - Chemistry_Form_2

Chemistry
for Secondary Schools

Charge = 0 Charge = +1

FOR ONLINE READING ONLY

Loses one electron

A stable ion
An unstable atom

Figure 3.2: Electron arrangement in sodium atom and its ion

Electrovalent bonding
Electrovalent bonding, also known as ionic bonding, is a type of chemical bond
formed when one atom transfers electrons to another, resulting in the formation
of positively and negatively charged ions. These charged ions attract each other
due to their opposite charges.

Electrovalent bonding usually occurs between a metal and a non-metal. The
metal loses electron(s) and the non-metal gains electron(s). For example, when
sodium and chlorine react to form sodium chloride, the sodium atom must lose
an electron to acquire a stable noble gas structure of neon, while the chlorine
atom must gain an electron to acquire a stable noble gas structure of argon. This
results in a positively charged sodium ion and a negatively charged chloride ion
which attract each other to form sodium chloride as shown in Figure 3.3. For this
chapter, electrons are represented by dots with different colours.

48 Student’s Book Form Two

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CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 48