Unit 1 – Atomic Theory
Unit Test
Time: 1 Hr Marks : 25
Section A (10 ´ 1 =
10)
Answer all the questions
I.
Choose the correct answer
1. Alpha
particles are emitted by ………
(a) hydrogen (b)
oxygen (c)
barium (d)
uranium
2. The
mass of the atom is due to ………
(a)
the electrons present in an atom
(b)
the protons and neutrons present in the nucleus
(c)
the protons, neurons and electrons present in the atom
(d)
neutrons present only
3. The
L and M shell, can have a maximum of ……… number of electrons respectively
(a)
2 and 8 (b)
8 and 18 (c) 18 and 32 (d) 8 and 32
II. True or False
4. Atomic
weight can be fractional.
5. Isotopes
of an element have different number of neutrons
6. The
mass of an electron is about 1/200 times the mass of hydrogen atom
III. Fill in the Blanks
7. The
radioactive isotope of hydrogen is ………
8. The
particles used by
IV. Give Reasons
9. Hydrogen
and deuterium have similar chemical properties.
10.
Section B (5 ´ 2 =
10)
Answer any five questions
11. Hydrogen
has three isotopes 
. Explain why there are electrically neutral?
12. Which
of the following pairs are isotopes? Give reason for your choice
(a) 
(b) 
13. Draw the atomic model of Silicon
14. Draw the atomic model of Chlorine
15. Name the important sub-atomic particles
16. What is the effect of magnetic field on
cathode rays and anode rays
17. Distinguish between a proton and a neutron.
Section C (1 ´ 5 = 5)
Answer any one of the
following
18. Explain
(OR)
Mention
the properties of anode rays