1. Isobars do not differ in the number of

2. 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

3.  What was the source of alpha particles in Rutherford scattering experiment?

4.  What prevents an atom from being collapsed?

5. Rutherford’s ‘alpha (α) particles scattering experiment’ resulted in the discovery of

6. What property of an element determines its chemical behaviour?

7. Why do most of the elements try to participate in the chemical combinations?

i. To gain more electrons

ii. To achieve Inert Gas configuration

iii. To complete their octet

iv. To complete their inner shells

Choose the correct option among the following

8. Which of the following are called nucleon?

9. . Which of the following elements does not exhibit the electrovalencey?

10. Which of the following statement is always correct?

11. 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
(ii) Bohr’s atomic model

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

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

14. Which one of the following is a correct electronic configuration of sodium?

15. Isotopes of an element have:

16. Which radioactive element is used in the treatment of cancer?

17. The first model of an atom was given by

18. Which of the following correctly represents the electronic distribution in the Mg atom?

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

20. An alpha particle is also known as: