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1. Class – IX
Subject – chemistry
Topic – Formula of compounds

2. Name of element = Oxygen
Name of element=hydrogen
Valency of hydrogen = 1
Valency of Oxygen = 2

3. Name of element = sodium
Name of element=chloride
Valency of sodium= 1
Valency of chloride = 1
Symbol Na Cl
Valency 1 1

4. Name of element = Aluminium
Name of element=Oxide
Charge of Aluminium= 3+
Charge of Oxide = 2-
Symbol Al O
Charge 3+ 2-
Formula : Al2o3

5. Symbol Ca O
Charge 2+ 2-
Formula : Ca2o2

6. Symbol / formula Cu No3
Charge 2+ 1-
Formula :Cu(No3)2

7. Name of element = Sulphur
Symbol = S
Atomic number =16
Number of protons= 16
Number of neutrons = 16
Number of electrons = 16
Distribution of electron = K L M N
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8. class IX science book