Page 1 - 4.HOME ASSIGNMENT-(ISOTOPES AND ISOBARS)TRONS IN VARIOUS SHELLS)

SAI International School
Class-IX
Subject-Chemistry
Topic-Structure of atom
Sub topic- Isotopes and Isobars
OBJECTIVE QUESTIONS
12
14
Q.1 Assertion: C and C are isotopes
Reason: Isotopes have same mass number but different atomic number.
Q.2 Assertion: Cobalt and Argon are isotopes

Reason: Cobalt and Argon have same mass numbers.

Q.3 Assertion: Protium and Tritium are isotopes
Reason: Isotopes have same atomic number and different mass number.
40
40
Q.4 Assertion: K and Ca are isobars.
Reason: The have same number of nucleons.
Q.5 Assertion: Co is used in treatment of cancer.
60
Reason: It produces gamma rays which is used in radio therapy.
Q.6 Which of the following pairs are isobars?
58
(a) 26A & 28B
58
79
80
(b) 35X & 35Y
25
(c) 12A & 12 B
24
(d) 6X & 6Y
14
13
Q.7 Isotope of which of the following element is used in determination of age of
fossils?
(a) Carbon
(b) Uranium
(c) Sulphur
(d) Iodine
Q.8 Argon and Calcium are -------------- because they have ----------- atomic
number and -------------- mass number.

SUBJECTIVE
S.LNo. Questions Mark Skill
Q.1 Which radioactive isotope is used to determine the activity of thyroid 1 E/R
gland?

Q.2 What name is given to the atoms of the same element which 1 Av/A
contain the same number of protons and electrons but different
number of nutrons.
Q.3 The composition of two atoms are given below: 3 Av/A
X Y
Protons: 8 8
Neutrons: 8 9
Electrons: 8 8
(a) What is the mass number of X?

1