Question

Describe the lonization periodic trends for atomic size, energy, and metallic character. Defore and give an example of each of the following classes of reactions, precipitation, acz gas evolution, redox (non combustion) and combe combustion. stion), and

Answer 1

Atomic size:- Generally atomic size increases from top to bottom in a group and decreases from left to right in a period.

For e.g. size of F, Cl , Br , I increases in order F<Cl<Br<I . These are elements of 17th group.

Ionization energy:- There is no regular trend for ionization energy. But generally it decreases from top to bottom in a group and increases from left to right in a period.

But this trend not follows sometimes. For example, in case of O and N the first ionization energy of O should be greater than that of N as O lies right to N . But actually first ionization energy of N is greater than that of O because in N electron is removed from half filled 2p orbital.

Metallic character:- metallic character is increases from top to bottom in a group and decreases from left to right in a period.

Metals have property to loose electrons. So we can say that less is ionization energy , more is metallic character. For example metallic character of Cs is more than Li . As Li lies in 2nd period and Cs lies in 6th period.

Precipitation reaction:- It is the reaction in which two ionic liquid reacts to form a solid product.

For example:-

Acid Base reaction :- In this type of reaction an acid and an base react to form salt and water. For example-

- Na, sou caa) + Bada (anat + sol (Bot20) Basaust gnal laa) ppt. (2rvat+2 c) NA

- NaOH + HCl Base Nad + H₂O salt water auch

Gas evolution :- These are the reaction in which one of the product is gas . For example-

Redox reaction :- These are the reactions in which reduction of a species and oxidation of another species occurs in a single reaction. For example:

૧ (s) + 3 Hot) – A toH), H ૮૧ ૧)

Combustion reaction:- This reaction is an exothermic redox reaction. For example-

Reduction aby Mees in Cu O + H - Cu + H₂O oridation.

CHu +20 (9) (9) CO2 + 2H₂O (9) (9)