PlayTest #3 - Army school

The first model of an atom was given by

• N. Bohr

• E.Goldstein

• Rutherford

• J.J Thomson

An atom with 3 protons and 4 neutrons will have a valency of

• 3

• 7

• 1

• 4

How many electrons are present in M-shell of an element with atomic number 20?

• 5

• 8

• 12

• 18

An alpha particle is also known as

• subatomic particle

• an unionised helium atom

• a neutral particle

• a doubly-charged helium ion

Which of the following isotope is used in the treatment of blood cancer?

• P-32

• I-131

• Co-60

• None of these

Isobars do not differ in the number of

• protons

• electrons

• neutrons

• nucleons

Which of the following correctly represents the electronic distribution in the mg atom?

• 3,8,1

• 2,8,2

• 1,8,3

• 8,2,2

Rutherford's 'alpha α particles scattering experiment' resulted in the discovery of

• electron

• proton

• nucleus in the atom

• atomic mass

Which of the following statement is always correct?

• An atom has equal number of electrons and protons.

• An atom has equal number electrons and neutrons.

• An atom has equal number of protons and neutrons.

• An atom has equal number of electrons, protons ans neutrons.

Cathode rays consist of negatively charged particles known as

• Electrons

• Protons

• Neutrons

• None of these