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Valency & Writing Chemical Formula - Atoms & Molecules Video Lecture - Class 9

FAQs on Valency & Writing Chemical Formula - Atoms & Molecules Video Lecture - Class 9

1. What is valency in chemistry?
Ans. Valency in chemistry refers to the combining capacity of an element with other elements. It indicates the number of electrons an atom can gain, lose, or share to form chemical bonds with other atoms. Valency helps in determining the chemical formula of a compound.
2. How is valency determined for an element?
Ans. Valency of an element can be determined by its position in the periodic table. Elements in groups 1, 2, 13, 14, 15, 16, 17, and 18 usually have a fixed valency. For example, elements in group 1 have a valency of +1, while elements in group 17 have a valency of -1. Transition metals may have varying valencies depending on the compound they form.
3. What is the meaning of a chemical formula?
Ans. A chemical formula represents the composition of a compound using symbols and subscripts. It shows the types and ratios of atoms present in a compound. For example, the chemical formula H2O represents water, where "H" represents hydrogen and "O" represents oxygen. The subscript "2" indicates that there are two hydrogen atoms for every oxygen atom.
4. How do you write a chemical formula from the valency of elements?
Ans. To write a chemical formula, you need to balance the valencies of the elements involved. The valency of one element becomes the subscript of the other element, and vice versa. For example, if sodium (Na) has a valency of +1 and chlorine (Cl) has a valency of -1, the chemical formula for sodium chloride would be NaCl.
5. Can the valency of an element change?
Ans. Yes, the valency of an element can change depending on the compound it forms. Elements from groups 13 to 17 in the periodic table can have multiple valencies. For example, nitrogen (N) can have a valency of either +3 or -3, depending on the compound it is part of. The valency of transition metals can also vary due to their ability to form different ions.
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