The Structure of Atom Worksheet-3

The Structure of Atom Worksheet-3

1. J. J. Thomson was highly eccouraged by the discovery of the electrons. He was the first to predict the picture of the atom known as the Thomson’s Model in the year 1899. Of all his observations the one that is still accepted is

(a) Atom is electrically neutral and has no net charge

(b) Electrons move around the nucleus in stationery orbits.

(c) The negative charge electrons may be studded or embedded in the sphere.

(d) The atom is a positively charged sphere in which protons are present.

2. The atomic model given by Rutherford was challenged by Maxwell radiation Theory. The radiation theory of Maxwell States that

(a) The charged particles around a circular orbit cannot move with fast speed.

(b) The electrons are electrically neutral

(c) The charged particles moving in circular orbits with fast speed emit energy in the form of radiations.

(d) The electrons are not able to move in circular orbits but only in elliptical orbits.

3. A noble gas with an octet structure in its valence shell with an atomic number 54 is

(a) Helium        (b) Radon          (c) Krypton       (d) Xenon

4. The radioisotope of element Cobalt, i.e. Co⁶⁰ is used for cancer treatment. The atomic number of Cobalt is

(a) 27                  (b) 21                  (c) 23                  (d) 26

5. The size of the atom is measured in terms of Angstorm units. How many metres is 1 angstorm equal to

(a) 10^–10            (b) 10^–9              (c) 10^-8               (d) 10^–7

6. If Rutherford’s atomic model, the electrostatic force at attraction between the positively and negatively charged particles is counter balanced by:

(a) The centripetal force exerted on the electrons moving in circular path.

(b) The high velocity of the electrons moving in a circular path.

(c) The linear movement of the nucleus

(d) None of these

7. Canal ray experiment lead to the discovery of:

(a) Protons        (b) Neutrons     (c) Electrons     (d) Nucleus

8. Which of the following particles explains the existence of isotopes?

(a) Electron       (b) Neutron       (c) Photon         (d) Proton

9. Which of the following statements is wrong about isotopes?

(a) Isotopes have same number of electrons

(b) Isotopes have same number of neutrons

(c) Isotopes have same chemical properties

(d) Isotopes have same number of protons

10. Which of the following is a pair of isobar?

(a) ₇N¹⁵, ₈O¹⁶     (b) ₆C¹³, ₇N¹³     (c) ₆C¹³, ₇N¹⁴      (d) ₆C¹³, ₈O¹⁵

Answer Key:

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