EASY
9th CBSE
IMPORTANT
Earn 100

What is the atomic number and mass number of the element whose atomic structure is shown in below?

Important Questions on Structure of the Atom

EASY
9th CBSE
IMPORTANT

In the Thomson's model of atom, which of the following statements are correct?

(i) The mass of the atom is assumed to be uniformly distributed over the atom.

(ii) The positive charge is assumed to be uniformly distributed over the atom.

(iii) The electrons are uniformly distributed in the positively charged sphere.

(iv) The electrons attract each other to stabilise the atom.

EASY
9th CBSE
IMPORTANT
The atomic number of an element is 13 and its mass, mass number is 27. The correct order representing the number of electrons, protons and neutrons respectively in this atom is.
EASY
9th CBSE
IMPORTANT

The following diagram depicts the Rutherford’s experiment.

Question Image

Why was zinc sulphide screen is used in the experiment?
EASY
9th CBSE
IMPORTANT

Atomic models have been improved over the years. Arrange the following atomic models in the order of their chronological order.

(i) Rutherford's atomic model

(ii) Thomson's atomic model

(iii) Bohr's atomic model.

EASY
9th CBSE
IMPORTANT

Which of the following are true for an element?

(i )Atomic number = Number of protons + number of electrons

(ii) Mass number = Number of protons+ number of neutrons

(iii) Atomic mass = Number of protons= Number of neutrons

(iv) Atomic number = Number of protons= Number of electrons.

EASY
9th CBSE
IMPORTANT
The number of electrons in an element X is 18 and the number of neutrons is 22. Which of the following is the correct representation of the element? 
EASY
9th CBSE
IMPORTANT

Different isotopes are matched with their uses as

(i) Co-60-To treat cancer

(ii) U-238-To produce electricity

(iii) I-131-To treat goitre

(iv) Na-24-In agricultural research

Which of the above matches are correct?

EASY
9th CBSE
IMPORTANT
In a sample of ethyl ethanoate(CH3COOC2H5) the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?