1. Rutherford’s experiment which established the nuclear model of the atom used a beam of

a) β-particles which impinged on the metal foil and got absorbed b) γ-rays which impinged on a metal foil and ejected electrons c) hydrogen atoms, which impinged on a metal foil and got scattered d) α-particles nuclei, which impinged on a metal foil and got scattered.

2. Isotopes have

a) same physical and chemical properties b) same physical properties but different chemical properties c) same chemical properties but different physical properties d) different physical and chemical properties.

3. Select the pair of isobars from the following species : 17A37, 17B35, 18C37, 18D36, 19E38

a) A and B b) A and C c) C and E d) C and D

4. Maximum number of electrons in any orbit is a) n2 b) 2n2 c) 1/2n2 d) none of these.

5. Na+ ion is isoelectronic with a) Li+ b) Mg2+ c) Ca2+ d) Ba2+

6. Which of the following electronic configurations is wrong?

a) Li = 2, 1 b) O = 2, 6 c) S = 2, 6, 8 d) P = 2, 8, 5

7. MgCl2 is the formula for an ionic compound of magnesium and chlorine. If the charge on Cl is -1, then the charge on Mg must be a) +2 b) +3 c) -2 d) -3

8. Isotones have

a) same mass number but different atomic numbers b) same atomic number but different mass numbers c) same value of (mass number - atomic number) d) same number of electrons.

9. The main drawback of Rutherford’s model of the atom is that

a) it does not explain the stability of atom b) it does not show the location of protons

c) it does not explain neutral nature of an atom d) it does not explain existence of a nucleus in an atom.

10. How many electrons are present in the M shell of an atom of an element with atomic number 23?

a) 5 b) 6 c) 12 d) 11

11. The ratio between number of neutrons in C and Si with respect to atomic mass 12 and 28 is a) 2:3 b) 3:2 c) 3:7 d) 7:3

12. An element M has a atomic mass 19 and atomic number 9, its ion is represented by

a) M+ b) M2+ c) M− d) M2−

13. Which of the following do not have the same number of valence electrons?

a) H, Li, Na, K b) He, Mg, Be, Ca c) B, Al, N, P d) O, S, Se

14. The triad of nuclei, which is isotone, is

a) 6C14 , 7N15, 9F17 b) 6C12, 7N14, 9F19 c) 6C14, 7N14, 9F17 d) 6C14, 7N14, 9F19.

15. The electronic configuration of elements A, B, C and D are (2, 8, 1),(2, 8, 2),(2, 8, 6) and (2, 8, 7) respectively. Which of them can make an ion with two negative charges?

a) A b) B c) C d) D

16. What will be the valency of an atom if its outermost shell contains four electrons?

a)8 b)4 c)2 d)6

17. A has 9 protons, 9 electrons and 10 neutrons,  has 12 protons, 12 electrons and 12 neutrons. Formula of the compound between  and  is

a) b) c) d)
18. How many total protons are found in one molecule of retinol (  )?

a)51 b)151 c)600 d)158

19. An element  has atomic mass 39 and atomic number 19. Which one of the following ions it will form on ionising one electron?

a)ion b)ion c)ion d)ion

20. Which of the following has more electrons than neutrons?

a) b) c) d)

21. The relative atomic mass of naturally occurring chlorine is not a whole number. What is the reason for this?

a) Chlorine atoms can have different numbers of neutrons. b) Naturally occurring chlorine cannot be obtained pure. c) Chlorine is unstable. d)The mass of the electrons has been included.

22. An element  has 9 protons and its valency is 1 . Another element  has valency 3 and 5 . What is the difference in the number of electrons in  and  ?

a)6 b)5 c)4 d)3

23. The nucleon number of atom  is 37. It exists as a diatomic molecule, . One molecule of  contains 34 protons. How many neutrons are present in the nucleus of atom  ?

a) 17 b) 20 c) 21 d) 25

24. Chlorine atom does not differ from the chloride ion in which of the following context?

a)  Electron b) Volume c) Proton d) Chemical reactivity

25. Which one of the following is not isoelectronic with neon atom?

a) 2O2- b) 11Na+ c) 9F- d) 12Mg+

26. Element  has 5 electrons in its  shell while element  has 5 electrons in its  shell. Which of the following statements is correct regarding elements  and  ?

a) Both elements have valency equal to 5 only. b) Both elements have the same mass number.

c) Atomic number of element  is 7 and that of element  is 15. d) Both elements show valency equal to 3 only.

27. An ion having a mass number 52 has 3 units of positive charge. The number of neutrons in the ion exceeds the number of electrons in it by 7 . The atomic number of the element is

a) 28 b) 22 c) 26 d) 24

28. The atomic masses of two isotopes of chlorine are 35 and 37. The number of neutrons respectively will be

a)18,20 b)20,18 c)17,18 d)18,17

29. Rutherford's model of an atom could not explain its stability. This was overcome by another atomic model. The postulates of the new model of atom are
(i) an atom consists of a positively charged sphere and the electrons are embedded in it
(ii) each shell or orbit corresponds to a definite energy, therefore, these circular shells are also  known as energy shells
(iii) as long as the electrons revolve in the stationary orbit it neither radiates nor absorbs energy.

a) (i) and (ii) b) (ii) and (iii) c) (i) and (iii) d) (i), (ii) and (iii)

30. In Rutherford's gold foil experiment most of the -particles pass through the gold foil without any deviation from their paths. This indicates that

a) the atom is spherical b) there is a positively charged nucleus at the centre of the atom

c)  the entire mass of the atom is concentrated at the nucleus of the atom d) most portion of the atom is empty space.

1

D

2

C

3

B

4

B

5

B

6

C

7

A

8

C

9

A

10

C

11

C

12

C

13

C

14

A

15

C

16

B

17

A

18

D

19

A

20

C

21

A

22

A

23

B

24

C

25

D

26

C

27

D

28

A

29

B

30

D