E-content for class IX prepared by nvs

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Structure of atom - all important MCQ type questions with answer

1.   Where are protons located in an atom ?

 (A)  Around the nucleus                                      

 (B) Inside the nucleus 

 (C) Both (A) & (B)                                              

 (D) None of these

Ans-B

2.  Which of the following statements is true ?

 (A)  A proton is 1837 times heavier than an electron.

 (B)  A proton is 1/1837 times heavier than an electron.

      (C)  A proton is 1/1837 times lighter than an electron.

      (D)  Proton has the same mass as an electron.

    Ans- a

3.     When alpha particles are sent through a thin metal foil, most of them go straight through the foil because  

(A)  alpha particles are much heavier than electrons.

(B)  alpha particles are positively charged.    

(C)  most part of the atom is empty.

(D)  alpha particles move with high velocity.

Ans-c

4.     Rutherford’s scattering experiment is related to the size of –

 (A)  nucleus                   (B) atom                       (C) electron (D) neutron

5.     The mass of a proton is –

  (A) 1.00728 amu           (B) 1.673 × 10^-24 gm      

  (C) 1.673 × 10^-27 kg     (D) all of these

6.     Rutherford performed his alpha scattering experiment using -

      (A)  silver                       (B) gold                         (C) mercury (D) diamond

7.    A proton is usually represented as –

     (A)   ¹p₁       

     (B)   ¹H ₁

           (C)    ⁴ He₂

           (D)  both (A) & (B)

   8.   The protons and neutrons are collectively called 

(A)  deuterons               

(B) positrons                

(C) mesons

(D) nucleons

    9.    -----------contains ²³₁₁Na -

(A)  22 protons     

(B) 22 neutrons     

(C) 12 neutrons

(D) None of these

10.  The credit of discovering neutron goes to -

  (A)  Rutherford              

(B) Thomson                 

  (C) Goldstein                 

(D) Chadwick

11.  The formula that gives the maximum number of electrons in a particular shell is -

(A) n²      (B) 2n²                          (C) 2n           (D)   n²/ 2 

 12. The radius of an atomic nucleus is of the order of -

(A) 10^-10 cm                  

(B) 10^-13 cm                  

(C) 10^-15 cm     

(D) 10^-8 cm

13.  A p-orbital can accommodate upto -

(A)  4 electrons              

(B) 2 electrons     

(C) 6 electrons (D) 3 electrons

14.   Energy levels are designated as -

(A)  K, L, M, N and so on

(B)  k, l, m, n and so on

(C)  I, II, III, IV and so on

(D)  All of these

15.    A neutron is represented as -

(A)    0 n⁰

(B)   1n¹

(C)   1  n⁰

(D)   1 n⁻ ¹

16.  The different subshells in an atom are represented as -

(A)  s,p,d,f                     (B) S,P,D,F                   (C) 1,2,3,4 (D) All of these

17.   The maximum number of electrons is N shell is -

(A) 2     

(B) 8     

(C) 18     

(D) 32

18.   The maximum number of electrons is f - subshell is -

(A) 5      (B) 6        (C) 14                                    (D) 10

19.          The maximum number of electrons that can be accommodated in the valence shell of an atom is - (A) 5                                  (B) 6                             (C) 7 (D) 8

20.   The maximum number of orbitals in f - subshell are -

(A) 1                             (B) 3                             (C) 5                                    (D) 7

21. Number of valence electrons-

  A). 1                             B) 2 

  C) 3                              D)    4

22.  The valency of ₁₀Ne = 2,8 is

(A) 10 

B) 8

C) 2

D) 0

23Which of the following has the same number of protons, electrons & neutrons?

(A) ⁵⁴ X₂₇ (B) ⁵⁵ X⁺¹₂₇

(C)    ⁵⁴ X₂₆  (D)    ⁵⁵ X⁺₂₈

24. In an atom there are four orbits, the maximum number of electrons in this atom will be –

(A) 30        

(B) 36     

(C) 32            

(D) 62

25.  Isotones of an element have –

(A)  same number of electrons              

(B) same number of protons

(C) same number of neutrons                            

(D) same number of neutrons & protons

26.   An isotone of 76 Ge is -32

(A)    ⁷⁷ Ga₃₂

(B)   ⁷⁷ As ₃₃

(C)    ⁷⁷ Se₃₄

(D)    ⁷⁹ Se₃₄

27.   Many elements have non - integral masses because –

(A)  they have isobars.

(B)  their isotopes have non - integral masses.

(C)  they have isotopes.

(D)  The constituent’s neutrons, protons & electrons combine to give fractional masses.

28. A deuteron contains –

(A)  a neutron & a positron.       

(B) a neutron & a proton.

(C) a neutron & 2 protons                                  

(D) 2 neutrons & a protons.

29. The triad of nuclei that is isotonic is –

(A) 14 C,15 N,17 F

(B) 12 C,14 N,19 F(C) 14 C,14 N,17 F

(D) 14 C,14 N,19 F

30.   Pick out the isoelectronic structures from the following -

(I)  CH₃ ⁺                        

(II) H₃O⁺                

(III) NH₃

(IV) CH₃^-

(A) I and II 

(B) III and IV                

(C) I and III                           

(D) II, III, IV

31. Two atoms of the same element are found to have different number of neutrons in their nuclei. These two atoms are –

(A) isomers                  

(B) isotopes                 

(C) isobars                                   

(D) allotropes

32. Members of which of the following have similar chemical properties?

(A) Isotopes                                                     

(B) Isobars

(C) Allotropes                                                   

(D) Both isotopes & allotropes

33. An atom which as a mass number of 14 & 8 neutrons is an –

(A) isotope of oxygen                                        

(B) isobar of oxygen

(C) isotope of carbon                                        

(D) isobar of carbon

34.   The electronic configuration of Mn⁺² is -

(A) 2, 8, 13                                                    

(B) 2, 8, 11, 2

(C) 2, 8, 13, 2                                                   

(D) None of these

35.     The number of electrons in the L - shell of phosphorus is not equal to that in the -

(A) L - shell of neon                                          

(B) M - shell of potassium

(C) M - shell of chromium                                  

(D) M - shell of argon

36.  Why is the valency of inert gases zero ?

37.  Find out the number of electrons, protons and neutrons in the following –

(a)  oxygen atom                       

 (b) oxide ion (O^-2)

(c) oxygen molecule

38.  Which isotope of hydrogen is present in heavy water ?

39. Ar (40) & Ca (40) have the same mass number but their properties are entirely difference. Why?