This document defines ions as positively or negatively charged atoms or groups of atoms. It describes two types of ions - cations, which are positively charged and formed when an atom loses electrons, and anions, which are negatively charged and formed when an atom gains electrons. Examples of common cations include sodium (Na+) and magnesium (Mg2+), while examples of common anions include chloride (Cl-) and oxide (O2-). The document explains that ions are formed through gains or losses of electrons, resulting in an unequal number of protons and electrons that creates a positive or negative charge.

1. Class - 9th
Ions(Cation and anion)
Bittu Kumar
Integrated B.Sc. - B.Ed.
School of Education, LPU

2. IONS
An ion is a positively or negatively charged atom (or
group of atoms).
Examples of the ions are : sodium ion, Na+, magnesium ion,
Mg2+, chloride ion, Cl–, and oxide ion, O2–.

3. An ion is formed by the loss or gain of electrons by an
atom, so it contains an unequal number of electrons and
protons.

4. There are two
types of ions : cations and anions.

5. 1. A Positively Charged Ion is Known as
Cation

6. Cation formation

7. A cation is formed by the loss of one or
more electrons by an atom.
For example, sodium atom loses 1 electron to
form a sodium ion, Na+, which is a cation.

8. Anion
An anion is formed by the gain of one or more
electrons by an atom.
For example, a chlorine atom gains (accepts) 1 electron to
form a chloride ion, Cl–, which is an anion

9. Why anion has a negative charge
• A normal atom contains an equal number of protons and
electrons, so it is electrical.
• Due to more electrons, than protons, an anion has a
negative charge on it.