CBSE Class 10 Chemistry Periodic Classification of Elements MCQs Set C

Question. The number of elements present in the 2nd, 3rd, 4th and 5th periods of the modern periodic table are:
a) 2,8,8,18
b) 8,8,18,32
c) 8,8,18, 18
d) 8,18,18,32

Question : The law of the modern periodic table was proposed by:
(a) H.G.I Moselly
(b) Dobereincer
(c) D.I. Mendeleev
(d) Newlands

Answer :  A

Question : Modern Periodic law is based upon:
(a) Number of neutrons
(b) Number of electron
(c) Atomic number
(d) Atomic mass

Answer :  C

Question : Assertion: There are 118 elements dis-covered so far.
Reason: Sulphur (16) belongs to Group 16 and belongs to 3rd period.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.

Answer :  B

Question : The statement that is not true about electron affinity is
(a) It causes energy to be released
(b) It causes energy to be absorbed
(c) It is expressed in electron volts
(d) It involves formation of an anion

Answer: B

Question : Down a group, the electron affinity __________.
(a) increases
(b) decreases
(c) remains same
(d) increases and then decreases

Answer : B

Question : The metal which is hard and has high melting point and used in filaments of electrical bulbs is
(a) Ni
(b) Fe
(c) Pt
(d) W

Answer :   D

Question : Pick out the chemically most reactive elements from the given triads.
Li, Na, K F, Cl, Br
(a) Li and F
(b) Li and Br
(c) K and F
(d) K and Br

Answer :   C 

Question : Upto which element, the Law of Octaves was found applicable?
(a) Oxygen
(b) Calcium
(c) Cobalt
(d) Potassium

Answer :  B

Question : An element has an atomic number of 15 with which of the following elements will it show similar chemical properties.
(a) Be (4)
(b) Ne (10)
(c) N (7)
(d) O (8)

Answer :  C

Question : An element ‘A’ belongs to the third period and group 16 of the Periodic Table. Find out the valency of A.
(a) Valency = 6
(b) Valency = 2
(c) Valency = 1
(d) Valency = 3

Answer :  B

Question. Mendeleev peridicted the existence of two elements and named them as eka-silicon and eka-aluminium. Identify the element which took their position at later stage.  
(a) Si and Ge
(b) Si and Ga
(c) Ge and Ga
(d) Si and Al

Answer : C

Question. Electronic configurations for four elements A, B, C and D are given below :   
A : 2,1 B : 2,8 C : 2,8,1 D : 2,8,8
Identify the correct statements.
(i) Elements A and B belong to the second period.
(ii) Elements A and C belong to the same group.
(iii) Element C is more reactive than element A.
(iv) Elements C and D belong to the third period
(a) (i) and (iii)
(b) (i), (ii) and (iii)
(c) (ii) and (iv)
(d) All the statements are correct.

Answer : D

Question. The correct order of increasing acidic nature of SO₂, SiO₂, P₂O₃ and Al₂O₃ is  
(a) SO₂ < P₂O₃ < SiO₂ < Al₂O₃
(b) Al₂O₃ < SiO₂ < SO₂ < P₂O₃
(c) Al₂O₃ < SiO₂ < P₂O₃ < SO₂
(d) SiO₂ < SO₂ < Al2O₃ < P₂O₃

Answer : C

Question. It was found that the law of octaves was applicable only upto  
(a) chlorine
(b) potassium
(c) calcium
(d) argon.

Answer : C

Question. The number of elements in third period of the periodic table is  
(a) 2
(b) 8
(c) 10
(d) 14

Answer : B

Question. The scientist who showed that the atomic number of an element is a more fundamental property than its atomic mass is   
(a) Henry Moseley
(b) Johann Wolfgang Dobereiner
(c) John Newlands
(d) Dmitri Ivanovich Mendeleev.

Answer : A

Question. “The properties of the elements are periodic function of their atomic numbers”. The statement was given by   
(a) N. Bohr
(b) J. W. Dobereiner
(c) D. I. Mendeleev
(d) H. G. J. Moseley.

Answer : D

Question. Which of the following orders of atomic radii is correctly represented?   
(a) B > C > N
(b) B > O > C
(c) C > B > N
(d) C > B > O

Answer : A

Question. Which statement about the elements in periodic table is correct?   
(a) The elements are arranged in order of increasing atomic mass.
(b) The elements in a period have the same number of outer electrons.
(c) The elements in a group have the same number of occupied electron shells.
(d) The non-metallic characteristic of the elements decreases down a group and increases across a period.

Answer : D

Question. Which is true about electronegativity order?   
(a) P > Si
(b) C > N
(c) Br > Cl
(d) Sr > Ca

Answer : A

Question. When Mendeleev started his work, the number of known elements were  
(a) 68
(b) 53
(c) 57
(d) 63

Answer : D

Question. The positions of four elements K, L, M and N in the periodic table are shown below :  

Which of the following statements are correct?
(I) K, L, M and N are metalloids.
(II) K is a metal while L, M and N are nonmetals.
(III) Among these four elements, K is the smallest in size.
(IV) K is a metal while L and M are metalloids and N is a non‑metal.
(a) II and III
(b) I and III
(c) III and IV
(d) None of these

Answer : B