(i) A chemical equation is a short hand representation of a chemical reaction with the help of chemical symbols and formulae.
(ii) Every chemical equation has two components : reactants and products.

Ion or radical is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

i) Anode rays travel in straight lines.
ii) Anode rays are made up of material particles.
iii) Anode rays are deflected by electric and magnetic fields.
iv) The properties of anode rays depend upon the nature of the gas taken inside in the discharge tube.
v) The mass of the particle is the same as the atomic mass of the gas taken inside the discharge tube.

Law of conservation of mass states that during any chemical change, the total mass of the products is equal to the total mass of the reactants".

J.J. Thomson found that cathode rays were attracted by the positively charged plate and repelled by the negatively charged plate. This led him to the conclusion that the cathode rays (electrons) were made of negatively charged particles.

\(\text { a) } \mathrm{C}+\mathrm{O}_{2} \rightarrow \mathrm{CO}_{2}\)
b) skeleton equation : \( \mathrm{P}+\mathrm{Cl}_{2} \rightarrow \mathrm{PCl}_{5} \)
Balanced equation : \( 4 \mathrm{P}+10 \mathrm{Cl}_{2} \rightarrow 4 \mathrm{PCl}_{5} \)
\(\text { c) } \mathrm{S}+\mathrm{O}_{2} \rightarrow \mathrm{SO}_{2}\)
c) skeleton equation : \(\mathrm{Mg}+\mathrm{HCl} \rightarrow \mathrm{MgCl}_{2}+\mathrm{H}_{2} \)
Balanced equation : \(\mathrm{Mg}+2 \mathrm{HCl} \rightarrow \mathrm{MgCl}_{2}+\mathrm{H}_{2} \)

a) NaCl - Na⁺ - Valency 1
b) CO₂ - C -  Valency 0
c) Al (PO₄) - Al⁺ - Valency 3
d) Ba (NO₃)₂ - Ba⁺ -  Valency 2
e) CaCl₂ -  Ca⁺ -  Valency 2