Class 11 Chemistry Chapter 3 Classification of Elements and Periodicity in Properties MCQs

Class 11 chemistry MCQs with answers are provided here for chapter 3 Classification of Elements and Periodicity in Properties. These MCQs are based on CBSE board curriculum and correspond to the most recent Class 11 chemistry syllabus. By practicing these Class 11 Multiple choice questions, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 11 Annual examinations as well as other entrance exams such as NEET and JEE.

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Class 12 Classification of Elements and Periodicity in Properties MCQs

1. The vertical columns in the periodic table are termed as ———-.

(a) periods

(b) groups

(c) series

(d) none of these

Ans: (b)

Ans: The vertical columns in the periodic table are termed as groups.

2. The element with atomic number 26 will be found in group :

(a) 2

(b) 8

(c) 6

(d) 10

Ans: (b)

Ans: The valence shell configuration of Z= 26 is [Ar] 3d⁶ 4s² . That for the group of element is 6 + 2 =8

3. The elements with atomic numbers 9, 17, 35, 53, 85 are all ———-

(a) halogens

(b) noble gases

(c) alkali earth metals

(d) transition metals

Ans: (a)

Solution: The elements of atomic numbers 9, 17, 35, 53, 85 are respectively F, Cl, Br, I, At etc are called halogen.

4. Which of the following electronic configurations of an atom has the lowest ionisation enthalpy?

(a) 1s² 2s² 2p³

(b) 1s² 2s² 2p⁶ 3s¹

(c) 1s² 2s² 2p⁶

(d) 1s² 2s² 2p⁵

Ans: (b)

Solution: Ionisation enthalpy is the amount of energy required when an electron is removed from the outermost orbit of an isolated gaseous atom. Electronic configuration of 1s² 2s² 2p⁶ 3s¹ has lowest ionisation enthalpy.

5. The Ionic radius of cation is always———

(a) Less than the atomic radius

(b) more than the atomic radius

(c) Equal to atomic radius

(d) Cannot be predicted

Ans: (a)

Solution: The Ionic radius of cation is always less than the atomic radius. Cation is formed by the loss of electrons. So that the effective nuclear charge increases as a result ionic radius decreases.

6. Which of the following elements has the maximum negative electron gain enthalpy?

(a) Oxygen

(b) Chlorine

(c) Fluorine

(d) Nitrogen

Ans: (b)

Solution: Chlorine has the maximum negative electron gain enthalpy.

7. The most electronegative element in the periodic table is———

(a) Nitrogen

(b) Oxygen

(c) Chlorine

(d) Fluorine

Ans: (d)

Solution: The most electronegative element in the periodic table is Fluorine

8. The elements of group 16 are called———-

(a) noble gases

(b) chalcogens

(c) halogens

(d) alkali metals

Ans: (b)

Solution: The elements of group 16 are called chalcogens.

9. In a group of the periodic table the Ionization enthalpies of the elements decreases from top to bottom because of ———-

(a) increase in densities

(b) decrease in chemical reactivities

(c) increase in atomic sizes

(d) decrease in electronegativities

Ans: (c)

Solution: In a group of the periodic table, the Ionization enthalpies of the elements decrease from top to bottom because of increase in atomic sizes.

10. The smallest ion among the following is

(a) Na⁺

(b) Al³⁺

(c) Mg²⁺

(d) Si⁴⁺

Ans: (d)

Solution: The isoelectronic ions Si⁴⁺, has the smallest size due to maximum nuclear charge.