Class 9 Structure of Atom

Rutherford’s alpha particle scattering experiment led to the discovery of :

• (a) Nucleus

• (b) Electrons

• (c) Protons

• (d) Neutrons

Which of the following is the correct electronic configuration of sodium ?

• 2,8,1

• 8,2,1

• 2,1,8

• 2,8,2

The particle not present in an ordinary hydrogen atom is :

• proton

• neutron

• nucleus

• electron

The subatomic particle called electron was discovered by:

• J. J. Thompson

• Neils Bohr

• James Chadwick

• E. Goldstein

Which of the following represents the correct electron distribution in magnesium ion ?

• 2,8

• 2,8,1

• 2,8,2

• 2,8,3

The correct electronic configuration of a chloride ion is :

• 2,8

• 2,8,4

• 2,8,8

• 2,8,7

Goldstein’s experiments which involved passing high voltage electricity through gases at very low pressure
resulted in the discovery of

• Electron

• Proton

• Nucleus

• Neutron

The number of electrons in the atom of an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of an atom of this element ?

• 
• 
• 
• 

The ion of an element has 3 positive charges. The mass number of atom of this element is 27 and the
number of neutrons is 14. What is the number of electrons in the ion ?

• 13

• 10

• 14

• 16

The first model of an atom was given by :

• Neils Bohr

• Ernest Rutherford

• J.J. Thomson

• Eugen Goldstein