Chemistry MCQs for NEET Exam on “s-Block Elements – Anomalous Behaviour of Beryllium”.
1. Which of the following element is different from the other group 2 elements?
a) magnesium
b) beryllium
c) calcium
d) strontium
Answer: b
Clarification: Beryllium, differs from the rest of the members of its group due to the following reasons: beryllium has a small atomic and ionic size, it has no vacant d-orbitals and it has a higher charge density comparatively.
2. Beryllium has ______________ melting point and is ______________ than the other members of its family.
a) low, smoother
b) low, harder
c) higher, harder
d) higher, smoother
Answer: c
Clarification: The points of difference are that the beryllium is denser and harder than other members of its family and it has a higher melting point that is 1551 Kelvin while that of magnesium is just 924 Kelvin. So we can say that beryllium has a higher melting point and is harder than other members of its family.
3. Does beryllium react with water?
a) Yes
b) No
c) Maybe
d) Cannot say
Answer: b
Clarification: Beryllium does not react with water even at a higher temperature while the other members of the family liberate hydrogen by reacting with water at room temperature, this is also one of the reasons of the anomalous behaviour of beryllium.
4. Beryllium Hydroxide is ______________ in nature.
a) acidic
b) basic
c) amphoteric
d) cannot say
Answer: c
Clarification: Beryllium oxide (BeO) and beryllium hydroxide [Be(OH)2] are amphoteric in character they also dissolve in acid to form a salt and beryllate in alkali. Beryllate is any salt containing an anion BeO22-.
5. Beryllium forms beryllium carbide on heating.
a) true
b) false
Answer: a
Clarification: Beryllium when heated with carbon forms beryllium carbide which on reaction with water gives methane, while the other members of the group form ionic carbide which is acetylide which on reaction with water evolves acetylene.
6. Beryllium and Aluminium are ______________ in nature.
a) electropositive
b) electronegative
c) metallic
d) fluorescent
Answer: b
Clarification: Beryllium’s and aluminium action with water is the same, they do not decompose with water or in the presence of water even at hundred degrees centigrade. This is probably due to their less electropositive character that is they are electronegative in nature.
7. Which of the following is a correct formula for sodium meta aluminate?
a) Na2AlO4
b) Na2Al2O
c) Na2Al2O4
d) NaAl2O4
Answer: c
Clarification: When aluminium reacts with alkali, that is when one mole of aluminium reacts with two moles of sodium hydroxide in presence of two moles of water two moles of sodium meta aluminate is formed along with three moles of hydrogen. The chemical formula for sodium meta aluminate is Na2Al2O4.
8. Aluminium and beryllium are ______________ in nature.
a) metallic
b) active
c) passive
d) electropositive
Answer: c
Clarification: Aluminium and beryllium are rendered passive on reaction with concentrated nitric acid, due to the formation of the oxide layer on their surfaces, this is one of the similarities between aluminium and beryllium.
9. Does beryllium form complexes?
a) Yes
b) No
c) Maybe
d) Cannot say
Answer: a
Clarification: Beryllium and aluminium form a number of complexes both form fluoro complex and ions, this is one of the similar chemical properties between beryllium and aluminium as they share a diagonal relationship.
10. Which of the following Statements do you think is true?
a) aluminium and beryllium are not stable in air
b) beryllium and aluminium share a diagonal relationship
c) the ionisation potential of beryllium is lower compared with its group
d) beryllium has a greater oxidation potential
Answer: b
Clarification: The correct statement is a beryllium and aluminium share a diagonal relationship, as aluminium and beryllium are stable in air, the ionization potential of beryllium has higher comparatively with its group and it has a lower oxidation potential.
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