Define valency by taking examples of silicon and oxygen.

Dear Student


Valency is the combining capacity of an atom.
Atomic number of oxygen = 8
Atomic number of silicon = 14
K L M
Electronic configuration of oxygen = 2 6 –
Electronic configuration of silicon = 2 8 4
In the atoms of oxygen the valence electrons are 6 (i.e., electrons in the outermost shell). To fill the orbit, 2 electrons are required. In the atom of silicon, the valence electrons are 4. To fill this orbit 4 electrons are required.
Hence, the combining capacity of oxygen is 2 and of silicon is 4.
i.e., Valency of oxygen = 2
Valency of silicon = 4


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