#### Atomic Structure One Mark Questions

9th Standard

Reg.No. :
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Science

Time : 00:30:00 Hrs
Total Marks : 20
5 x 1 = 5
1. Among the following the odd pair is

(a)

8O18, 17cl37

(b)

18Ar40,7N14

(c)

14Si30, 15pd31

(d)

24cr54, 19K39

2. The term nucleons refer to

(a)

Protons and electrons

(b)

only Neutrons

(c)

electrons and neutrons

(d)

Protons and neutrons

3. The correct electronic configuration of potassium is

(a)

2,8,9

(b)

2,8,1

(c)

2,8,8,1

(d)

2,8,8,3

4. Law of multiple proportions was proposed by _________

(a)

J. Ritcher

(b)

Rutherford

(c)

John Dalton

(d)

J.J Thomson

5. 2H2 + 02 $\longrightarrow$2H20. This is a___________ reaction.

(a)

Combination

(b)

Displacement

(c)

Decompostion

(d)

Exothermic

6. 5 x 1 = 5
7. _________isotope is used in the treatment of goiter

()

iodine 131

8. The number of neutrons present in $_{ 3 }^{ 7 }{ Li }$ is ------

()

4

9. The valency of Argon is ________

()

zero

10. Positive charges are concentrated in the central region of the atom called __________

()

Nucleus]

11. Bohr model was applicable only to _________

()

Hydrogen

12. 5 x 1 = 5
13. In an atom, electrons revolve around the nucleus in fixed orbits

(a) True
(b) False
14. Isotopes of an element have the different atomic numbers

(a) True
(b) False
15. Electrons have negligible mass and charge.

(a) True
(b) False
16. Beta particle is negatively charged and is identical with electron.

(a) True
(b) False
17. Orbit is the path by which electrons revolve around the nucleus.

(a) True
(b) False
18. 5 x 1 = 5
19. Dalton

20. (1)

Same atomic number but different mass number;

21. Thomson

22. (2)

Plum pudding model

23. Isotopes

24. (3)

$\alpha$-ray scattering experiment;

25. Rutherford

26. (4)

First atomic theory

27. Isobars

28. (5)

same mass number