Topic: The s-Block Elements (Test 1)



Topic: The s-Block Elements
Q.1

The general electronic configuration of nsexit in:        


A. alkaline earth metals.
B. coordination compounds
C. alkali metals.
D. transition elements
Answer : Option A
Explaination / Solution:

The general electronic configuration of ns2 exists in alkaline earth metals as their outer most electron enter the S orbital  and they have only two electrons in their valence shell

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Q.2
The alkali metals and their salts impart characteristic colour to an oxidizing flame because:
A. the largest atomic size makes them to emit radiation
B. the smallest atomic size makes them to absorb radiation
C. there is emission of radiation in the visible region from the excited electron
D. sufficient light energy is absorbed to make an atom gain an electron
Answer : Option C
Explaination / Solution:

Alkali metals have one unpaired electron in their valence shell which gets excited by absorbing the energy from flame, excited states are very unstable and quickly move back to lower state ,at that time they emit the energy in the form of radiation in visible reason of electromagnetic spectrum and is abserved as characteristic colour.

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Q.3
The s-block elements of the Periodic Table have only
A. one group
B. three groups
C. two groups.
D. four groups
Answer : Option C
Explaination / Solution:

s block comprises of only two groups alkali metal group and alkaline earth metal groups

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Q.4
Group I elements of the periodic table are collectively known as
A. transition elements
B. alkaline earth metals.
C. noble gases
D. alkali metals
Answer : Option D
Explaination / Solution:

Group I ( )elemens  react vigorously with water to produce an alkaline solution thus colectively known as alkali metals

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Q.5
Group IlA of the periodic table consists of the six elements are collectively known as
A. alkaline earth metals.
B. noble gases
C. transition elements
D. alkali metals.
Answer : Option A
Explaination / Solution:

because their oxide and hydroxide are alkaline in nature and these metal oxide are found in earth's crust

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Q.6
One of the following is not called alkaline earth metal.
A. Strontium
B. radium.
C. barium
D. beryllium,
Answer : Option D
Explaination / Solution:

Alkaline earth metals are called so because of two reasons

  1. Alkaline earth metals are obtained on earth in the form of ores
  2. Oxides and hydroxides of Alkaline earth metals are basic in nature,

However Beryllium fulfills 1st reason but its oxides and hydroxides are amphoteric so sometimes they say it is not alkaline earth metal. but as it is amphoteric IUPAC has accepted this as alkaline earth metal


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Q.7
Calcium and Magnesium belong to the category of
A. transition elements
B. Alkaline earth metals.
C. coordination compounds
D. alkali metals.
Answer : Option B
Explaination / Solution:

calcium and megnesium are 2nd group element of periodic table which are obtaine on earth in the form ore, their oxides and hydroxide are alkaline in nature so they are alkaline earth metals

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Q.8
Sodium and potassium belong to the category of
A. noble gases
B. alkali metals.
C. alkaline earth metals.
D. transition elements
Answer : Option B
Explaination / Solution:

Na and K are shiny, soft ,highly reactive metal at standard temprature and pressure and electronic configaration of Na & K  is ns2,,compounds of Na & K are available most aboundenty in nature so thees two are  alkali metal.

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Q.9
One of the following is highly radioactive
A. Francium
B. Lithium
C. Rubidium
D. Caesium
Answer : Option A
Explaination / Solution:

Fr is highly radioactive metal, that decays in to astatine,,radium and radon , it is also highly unstable element found only in trace amount on earth.

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Q.10
The diagonal relationship exists between
A. Lithium and magnesium
B. Lithium and aluminium
C. Lithium and beryllium
D. Beryllium and magnesium
Answer : Option A
Explaination / Solution:

Lithium shows diagonal relationship to Magnisium due to their nearly same polarising power, comparable electronegativities(Li=1.00, Mg=1.20) and small difference in radius (Li=152Pm, Mg=159pm).

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