The Structure of Atom Worksheet-2

The Structure of Atom Worksheet-2

1. The discovery of isobars proved that atoms of different elements need not de different in all aspects. Which among the following pairs are isobars

(a) Ar and Ca    (b) Na and Ca   (c) Li and Rb    (d) Ni and Cr

2. The neutron was discovered much later, by James Chadwick, after the discovery of the electron and the proton. Which of the following are believed to be the prime reason for the late discovery of the neutron?

(a) Because of its small size

(b) Because of its negligible mass

(c) Because it’s a chargeless particle

(d) Because of its less abundunce

3. Niels Bohr was the brain behind the concept of the Bohr’s Atomic Model. According to the Bohr’s Atomic Model there are specific orbits around the nucleus in which the electrons rotate. These specific orbits are known as:

(a) Orbitals                                    (b) Elliptical Paths

(c) Circular Paths                         (d) Stationary Orbits

4. Oxygen is a homonuclear diatomic molecule. Which of the following  can form a homonuclear octaatomic molecule

(a) Helium        (b) Sulphur       (c) Chlorine       (d) Phosphorus

5. Heteroatomic molecules are made up of two or more atoms of different elements. Example of a heteroatomic molecule which is also a liquid is

(a) Hydrogen Peroxide               (b) Hydrogen Chloride

(c) Ammonia                                 (d) Silver Chloride

6. Out of the following molecules and ions choose the one which has a octet structure of a noble gas

(a) Cl₂                 (b) He                 (c) Cl^–                 (d) Br

7. Which of the following molecules has a Duplet Structure in its valence shell?

(a) Sodium        (b) Lithium       (c) Helium         (d) Fluorine

8. Out of the following, predict which one is a metal?

(a) ₁₂P²⁴              (b) ₁₆Q³¹             (c) ₁₈R⁴⁰             (d) ₂S⁴

9. It is said that the discovery of radioactivity led to the discovery of the fundamental particles. The fundamental particles of an atom are electrons, protons and neutrons. An atom of a element has 9 protons, 9 electrons and 10 neutrons. Predict the element and its valency

(a) Li, 1               (b) Na, 1             (c) Cl, 1               (d) F, 1

10. Kalapakkam in Tamilnadu synthesizes heavy water from Deuterium, used in the Nuclear Plants all over India. Deuterium is an isotope of

(a) Hydrogen with mass number 1

(b) Hydrogen  with mass number 2

(c) Hydrogen with mass number  3

(d) Helium with mass number 4

Answer Key:

(1)-(a); (2)-(c); (3)-(d); (4)-(b); (5)-(a); (6)-(c); (7)-(c); (8)-(a); (9)-(d); (10)-(b)