CBSE Class 11 Chemistry s Block Elements MCQs Set B

Question: Group 2 elements are called alkaline earth metals why? Choose the correct reason(s).

(i) Hydroxides formed by group 2 elements are alkaline in nature.
(ii) Their metal oxides are found in the earth’s crust.
(iii) Their oxides are alkaline in nature
(iv) Group 2 elements react with alkalies

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

Answer: (i), (ii) and (iii)

Question: Which of the following alkali metal is highly radioactive?

• a) Francium
• b) Rubidium
• c) Caesium
• d) None of these

Answer: Francium

Question: Which of the following statements is not correct for alkali metals?

• a) Alkali metals exist in free state in nature.
• b) Alkali metals are the most electropositive metals
• c) These metals have the largest size in a particular period of the periodic table.
• d) None of these

Answer: Alkali metals exist in free state in nature.

Question: Which of the following has largest size ?

• a) Na^–
• b) Na
• c) Na⁺
• d) Can’t be predicted

Answer: Na^–

Question: Ionization potential of Na would be numerically the same as

• a) electronegativity of Na⁺
• b) ionization potential of Mg
• c) None of these
• d) electron affinity of Na⁺

Answer: electronegativity of Na⁺

Question: Which one of the following properties of alkali metals increases in magnitude as the atomic number rises ?

• a) Ionic radius
• b) Melting point
• c) Electronegativity
• d) First ionization energy

Answer: Ionic radius

Question: Which of the following has density greater than water?

• a) Rb
• b) Na
• c) Li
• d) K

Answer: Rb

Question: The elements of group 1 provide a colour to the flame of Bunsen burner due to

• a) low ionization potential
• b) low melting point
• c) softness
• d) presence of one electron in the outermost orbit

Answer: low ionization potential

Question: The metal that produces red-violet colour in the nonluminous flame is

• a) Rb
• b) Ba
• c) Ag
• d) Pb

Answer: Rb

Question: The alkali metals have low melting point. Which of the following alkali metal is expected to melt if the room temperature rises to 30°C?

• a) Cs
• b) K
• c) Na
• d) Rb

Answer: Cs

More Questions........................................

Question: In the case of the alkali metals

• a) the cation is smaller than the atom
• b) the cation and the atom have about the same size
• c) the cation is larger than the atom
• d) the cation is less stable than the atom

Answer: the cation is smaller than the atom

Question: The element which on burning in air gives peroxide is

• a) sodium
• b) caesium
• c) lithium
• d) rubidium

Answer: sodium

Question: Which one of the alkali metals, forms only, the normal oxide, M₂O on heating in air ?

• a) Li
• b) Rb
• c) K
• d) Na

Answer: Li

Question: Which of the following is used as a source of oxygen in space capsules, submarines and breathing masks ?

• a) KO₂
• b) Li₂O
• c) Both
• d) None of these

Answer: KO₂

Question: Which hydride is most stable

• a) LiH
• b) KH
• c) NaH
• d) CsH

Answer: LiH

Question: The most stable compound is

• a) LiF
• b) LiCl
• c) LiBr
• d) LiI

Answer: LiF

Question: Which of the following represents a correct sequence of reducing power of the following elements?

• a) Li > Cs > Rb
• b) Cs > Li > Rb
• c) Rb > Cs > Li
• d) Li > Rb > Cs

Answer: Li > Cs > Rb

Question: What is the colour of solution of alkali metals in liquid ammonia?

• a) Blue
• b) Violet
• c) Bronze
• d) Green

Answer: Blue

Question: Which is most basic in character ?

• a) CsOH
• b) NaOH
• c) KOH
• d) LiOH

Answer: CsOH

Question: Which compound will show the highest lattice energy

• a) NaF
• b) RbF
• c) CsF
• d) KF

Answer: NaF