Chemistry Class-11: Chapter –3. Classification of Elements and Periodicity in Properties-Part – 5

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Question: 23

An element belongs to 3rd period and group-13 of the periodic table. Which of the following properties will be shown by the element?

(i) Good conductor of electricity

(ii) Liquid, metallic

(iii) Solid, metallic

(iv) Solid, non-metallic


III. Short Answer Type

Question: 24

Explain why the electron gain enthalpy of fluorine is less negative than that of chlorine.


The added electron in fluorine goes to second quantum level. Due to small size of fluorine it experiences repulsion from other electrons much more in comparison to that in chlorine because in chlorine, the electron is added to 3rd quantum level in which larger space is available for movement.

Question: 25

All transition elements are d-block elements, but all d-block elements are not transition elements. Explain.


Outermost electronic configuration

Formula of Oxide

Question: 26

Identify the group and valency of the element having atomic number 119. Also predict the outermost electronic configuration and write the general formula of its oxide.


Compare your plot with the plot given in the textbook.

Question: 27

Ionization enthalpies of elements of second period are given below :

Ionization enthalpy

Match the correct enthalpy with the elements and complete the graph given in Fig. 3.1. Also write symbols of elements with their atomic number.

Ionization enthalpy

Ionization Enthalpy

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Compare your plot with the plot given in the textbook.