Question

TEST YOUR CONCEPTS

Very Short Answer Type Questions

1. How Rutherford’s theory contradicts the laws of

electrodynamics?

2. According to Dalton, atoms combine in ________

ratio to form compounds.

3. Which postulate of Dalton’s atomic theory is

considered to be correct even now?

4. What are the conditions maintained in a discharge

tube for the generation of cathode rays?

5. According to Rutherford electrons revolve around

the nucleus in ________

6. What are isotopes? Give an example.

7. What is an α-particle?

8. Give the geometrical representations of electronic

arrangements of the following elements:

(a) fluorine (b) phosphorus

9. What is the maximum number of electrons that can

be present in the nth shell of an atom?

10. What were the comparative values of diameter of

nucleus and atom given by Rutherford?

11. When electric field is applied, the cathode rays

bend towards ________.

12. Find the number of valence electrons in the

following elements by writing the electronic

arrangement in their atoms:

(a) nitrogen (b) sulphur (c) chlorine

13. Why Rutherford’s model is called nuclear model?

14. Define atomic number and mass number. How can

you represent an atom by using atomic number and

mass number? Give two examples.

15. Who discovered neutrons? How was the discovery

made?

16. Why is a partially evacuated discharge tube taken

for Thomson’s experiment?

17. Atoms of different elements having the same mass

number are known as ________.

18. The nature of ________ rays depends upon the

nature of the gas in the discharge tube.

19. How did Rutherford explain the stability of atom?

20. Name the isotopes of hydrogen and give the

number of neutrons present in each of them.

21. What is the relative mass of proton with respect to

hydrogen atom?

22. Which experiment led to the discovery of nucleus?

23. Most of the α-particles passed straight through the

gold foil. This proved the existence of _________

in an atom.

24. According to Rutherford, ________ force of

nucleus is balanced by the high velocity of revolving

electrons.

25. The atoms of the same element may differ in the

number of _________.

26. The valence shell of an element of atomic number

35 is the _________ shell.

27. Give the mass and charge of an electron, a proton

and a neutron in kg and coulombs, respectively.

28. According to Bohr’s atomic model, electrons

revolve in ________ orbits.

Short Answer Type Questions

29. Explain Thomson’s atomic model. What are the

drawbacks of this model?

30. An atom X is made up of 20 protons and 20

neutrons. Represent the atom with atomic number

and mass number.

31. Why does chlorine have fractional atomic mass?

32. How could Bohr explain the stability of an

atom?

33. Give the postulates of Dalton’s atomic theory.​

Answer 1

Answer:

I have tested my concept