Question

Write about valency and types.


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Answer 1

$\huge\bigstar\underline\mathfrak{Valency}$

It is the number of electrons lost or gained by any atom in its valence shell.

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Types :

It is of two types :

• Positive valency :

It is the number of electrons lost by the atom from its valence shell.

On losting the electrons, atom acquires positive charge, so valency is positive in nature. It happens when any atom is having less than four electrons in valence shell.

According to the number of electrons lost, valency may be +1, +2, +3.

Example :

Valency of sodium is +1

Valency of Calcium is +2.

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• Negative valency :

It is the number of electrons gained by the atom in its valence shell. According to the electrons gained it may be -1, -2, -3

It happens when atom contains more than 4 electrons in its valence shell.

Example :

Valency of chlorine is -1.

Valency of Oxygen is -2.

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Answer 2

Answer:

★ Valency

Valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules.

• There are two types of Valency:

1] ElectroValency:

If an element combines by the loss or gain of electrons to form electrovalent compounds (or ionic compounds), its valency is known as electrovalency.

2] CoValency:

If an element combines by the sharing of electrons to form covalent compounds (or molecular compounds), its valency is known as covalency.