Samacheer Kalvi Class 9 Science Atomic Structure Questions - 1

Question: 1

_____ and _____ has the same number of neutrons but different atomic numbers.

(A) Boron and Carbon

(B) Boron and Cobalt

(C) Cobalt and Beryllium

(D) Carbon and Beryllium

Ans: A

Boron and Carbon

Question: 2

Cobalt 60, a radioactive isotope is used for the treatment of

(A) Anemia

(B) Cancer

(C) Communicable disease

(D) Goiter

Ans: B


Question: 3

A reaction where two or more substances combine to form a single substance

(A) Combination reaction

(B) Double displacement reaction

(C) Displacement reaction

(D) Decomposition reaction

Ans: A

Combination reaction

Question: 4

The nuclear force that binds the protons and the neutrons is _____ than the gravitational force.

(A) Slightly greater

(B) Much greater

(C) Slightly lesser

(D) Much lesser

Ans: B

Much greater

Question: 5

When an electron absorbs energy, it jumps from _____ energy to higher energy force.

(A) Basic

(B) Lower

(C) Highest

(D) Normal

Ans: B


Question: 6

Electron was discovered by

(A) J.J. Thomson

(B) James Chadwick

(C) Rutherford

(D) Neils Bohr

Ans: A

J.J. Thomson

Question: 7

Atoms of same element with the same atomic number but different mass numbers are called

(A) Isomers

(B) Isotones

(C) Isotopes

(D) Isobars

Ans: C


Question: 8

Who explained the causes of the stability of the atom?

(A) Neils bohr

(B) James Chadwick

(C) John Dalton

(D) Rutherford

Ans: A

Neils bohr

Question: 9

Law of multiple proportions was proposed by

(A) Plato

(B) John Dalton

(C) Jeremias Ritcher

(D) Democritus

Ans: B

John Dalton

Question: 10

Which force is more powerful than gravity?

(A) Frictional force

(B) Newton's force

(C) Nuclear force

(D) Yukawa force

Ans: D

Yukawa force