Question 51.
Which of the following forms the basis of the modern periodic table?
(a) Atomic mass
(b) Atomic number
(c) Number of nucleons
(d) All of these
Answer: (b) Atomic Number
Question 52.
The electronic configuration of an element M is 2, 8, 4. In modern periodic table, the element M is
placed in
(a) 4th group
(b) 2nd group
(c) 14th group
(d) 18th group
Answer: (c) 14th group
Question 53.
Which one of the following statements is not correct about the trends in the properties of the elements
of a group on going down in a group?
(a) The chemical reactivity of metals increases.
(b) The metallic character of elements increases.
(c) The size of the atom increases.
(d) The valence electrons increase.
Answer: (d) The valence electrons increase.
Question 54.
Name the neutral atom in the Periodic Table which has the same number of electrons as K+ and Cl-.
(a) Helium
(b) Argon
(c) Neon
(d) Krypton
Answer: (b) Argon
Question 55.
Which of the following is the most reactive element of the group 17?
a) Oxygen
b) Sodium
c) Fluorine
d) Magnesium
Answer: (c) Flourine
Question 56.
Which of the following set of elements is written in order of their increasing metallic character?
(a) Na Li K
(b) C Q N
(c) Mg Al Si
(d) Be Mg Ca
Answer: (d) Be, Mg, Ca
Question 57.
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) Valency = 2
Question 58.
An element X combines with oxygen to form an oxide XO. This oxide is electrically con¬ducting. Write the
formula of the compound formed when X reacts with chlorine.
(a) XCl3
(b) XCl
(c) XCl2
(d) XCl5
Answer: (c) XCl2
Question 59.
The atom of an element has electronic con-figuration 2, 8, 7. To which of the following elements would
it be chemically similar?
(a) N(7)
(b) P(15)
(c) Na(11)
(d) F (9)
Answer: (d) F (9)
Question 60.
Which of the following is the correct order of the atomic radii of the elements oxygen, fluorine and
nitrogen?
(a) O < F < N
(b) N < F < O
(c) O < N < F
(d) F < O < N
Answer: (d) F < O < N
Question 61.
An element X has mass number 40 and contains 21 neutrons in its atom. To which group of the Periodic
Table does it belong?
(a) Group 1
(b) Group 4
(c) Group 2
(d) Group 3
Answer: (a) Group 1
Question 62.
Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. X would
most likely be in the same group of the Periodic Table as
(a) Na
(b) Mg
(c) Al
(d) Si
Answer: (b) Mg
Question 63.
Which of the following elements has 2 shells and both are completely filled?
a) Helium
b) Neon
c) Calcium
d) Boron
Answer: (b) Neon
Question 64.
What happens to the electropositive character of elements on moving from left to right in a periodic
table?
a) Increase
b) Decreases
c) First increases then decreases
d) First decreases then increases
Answer: (b) decreases
Question 65.
Out of F and Cl, which has higher electron affinity ?
(a) Cl
(b) F
(c) both have same
(d) none
Answer: (a) Cl
Question 66.
Which group elements are called transition metals?
a) Group number 1 to 2
b) Group number 13 to 18
c) Group number 3 to 12
d) Group number 1 to 8
Answer: (c) group no 3 to 12
Question 67.
Which option describes the achievements of the Mendeleev’s Periodic Table?
(a) prediction of noble gases
(b) it eliminated the blank spaces left in the table
(c) predicting that the elements can be arranged based on their properties
(d) an element in a trend has an average atomic mass of the elements above and below it
Answer: (a) prediction of noble gases
Question 68.
What relation do Ar and Ca have?
(a) isotopes
(b) isoelectronic
(c) isobars
(d) isotones
Answer: (c) isobars
Question 69.
Isotopes possess –
(a) same number of Protons
(b) same number of neutrons
(c) same mass number
(d)) none
Answer: (a) same number of Protons
Question 70.
On which factor does ionisation energy depend?
(a) Size of an atom
(b) nuclear charge
(c) electronic configuration
(d) all
Answer: (d) all
Question 71.
Which of the following sets of atomic number belong to that of alkali metals?
(a) 1, 12, 30, 4, 62
(b) 37, 19, 3, 55
(c) 9, 17, 35, 53
(d) 12, 20, 56, 88
Answer: (b) 37, 19, 3, 55
Question 72.
The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the
following categories does the element belong?
(a) Metal
(b) Metalloid
(c) Non-metal
(d) Left-hand side element
Answer: (b) Metalloid
Question 73.
Pick out the odd one –
(a) Argon
(b) Neon
(c) Barium
(d) Helium
Answer: (c) Barium
Question 74.
Which out of them is not a halogen?
(a) Flourine
(b) Chlorine
(c) Germanium
(d) Iodine
Answer: (c) Germanium
Question 75.
Which is biggest in size –
(a) Lithium
(b) Sodium
(c) Magnesium
(d) Pottasium
Answer: (d) Pottasium