S block Elements

 1. The chemical formula of baking powder is————-

(a) NaHCO3

(b) Na2CO3

(c) Na2SO4

(d) NaCl

Ans: (a)

Solution: The chemical formula of baking powder is NaHCO3

2. Which has the maximum electropositive character?

(a) Cu

(b) Cs

(c) Ba

(d) Cr

Ans: (b)

Solution: Cs being an alkali metal is maximum electropositive in nature.

3. When the washing soda is heated

(a) CO is released

(b) CO + CO2 is released

(c) CO2 is released

(d) water vapours are released

Ans: (d)

Solution: upon heating, washing soda loses water molecules and becomes anhydrous sodium carbonate which does not decompose upon further heating.

4. Which sulfate has the highest solubility in water?

(a) BaSO4

(b) CaSO4

(c) BeSO4

(d) MgSO4

Ans: (c)

Solution: BeSO4 has the highest solubility due to maximum hydration energy.

5. Which of the following metal ions plays an important role in muscle contraction?

(a) K+

(b) Na+

(c) Mg2+

(d) Ca2+

Ans: (d)

Solution: Ca2+ ions are involved in muscle contraction.

6. The correct order sequence of of the increasing covalent character is:

(a) LiCl < NaCl < BeCl2

(b) BeCl2 < LiCl < NaCl

(c) NaCl < LiCl < BeCl2

(d) BeCl2 < NaCl < LiCl

Ans: (c)

Solution: According to the Faizan rule greater the size of cation more is the ionic character, greater the charge on cation more is the covalent character. so the correct order of covalent character of the given compounds are NaCl < LiCl < BeCl2

7. Which of the following alkaline earth metal ions has the highest ionic mobility in aqua solution?

(a) Be2+

(b) Ca2+

(c) Ba2+

(d) Mg2+

Ans: (c)

Solution: The ionic mobility Is the maximum in Ba2+ ions since it has the least tendency to get hydrated.

8. Which one of the alkali metals form only the normal oxide M2O on heating in air?

(a) Rb

(b) K

(c) Li

(d) Na

Ans: (c)

Solution: Lithium forms normal oxide Li2O.

9. As the alkaline earth metal (except Be) tend to lose their valence electron readily they act as:

(a) weak oxidizing agents

(b) weak reducing agents

(c) strong oxidizing agents

(d) strong reducing agents

Ans: (d)

Solution: the alkaline earth metal (except Be) tends to lose its valence electrons readily and they act as strong reducing agents.

10. The alkaline earth metal present in chlorophyll is ———–

(a) Be

(b) Mg

(c) Se

(d) Ba

Ans: (b)

Solution: The alkaline earth metal present in chlorophyll is Magnesium (Mg).

Ques 1. Which alkaline earth metal is a component of Chlorophyll?

1. Ra
2. Ba
3. Be
4. Mg

Ans. (D) Mg

Explanation: Magnesium is the core atom of the chlorophyll molecule. A single chlorophyll molecule constitutes 6.7% of magnesium. It acts as a catalyst by activating enzymes involved in nucleic acid synthesis, respiration, and photosynthesis.

Ques 2. Which of the enlisted compounds is termed as slaked lime?

1. Calcium Oxide
2. Calcium Hydroxide
3. Calcium Sulfate
4. Calcium Carbonate

Ans. (B) Calcium Hydroxide

Explanation: Calcium Hydroxide is conventionally termed slaked lime. It is a colorless and crystalline white powder formed upon slaking calcium oxide with water. This process is termed hydration or lime slaking.

Ques 3. Which of the elements below has the most electro-positive properties?

1. Cs
2. Fr
3. Ba
4. Na

Ans. (A) Cs

Explanation: As the element is large in size, Cs (Cesium) has the least electron-proton attraction causing it to easily lose its electron to attain the most stable state. Thus, making it a highly electropositive element.

4. When dissolved in liquid ammonia, which color do alkali metals turn to?

1. Red color
2. Deep Blue
3. Colorless
4. Pink

Ans. (B) Deep blue

Explanation: Alkali metals turn to deep blue color as the alkali atom easily loses the valence electron in liquid ammonia. It combines with ammonia to form ammoniated cations and ammoniated electrons. The solution turns deep blue due to the presence of ammoniated electrons.

Read More: Difference between Cations and Anions

Ques 5. Which alkaline earth metal predominantly forms covalent compounds?

1. Ba
2. He
3. Be
4. Ra

Ans. (C) Be 

Explanation: Be (Beryllium) is small in size and contains only 2 electrons in the outermost valence shell. Considering it has a high charge-to-size ratio, Be has a high polarizing potential compared to other elements that resultantly form covalent bonds. 

Ques 6. What is Solvay’s process used for?

1. Manufacturing of Sodium Carbonate
2. Manufacturing of Potassium Carbonate
3. Manufacturing of Sodium Peroxide
4. Manufacturing of Sodium Hydroxide

Ans. (A) Manufacturing of Sodium Carbonate

Explanation: Also, termed the ammonia-soda process, the Solvay process is an industrial method used for extracting Sodium Carbonate from brine, ammonia, and limestone. It is named after the Belgian chemist, Ernest Solvay.

Ques 7. Which of the below-mentioned oxide is amphoteric?

1. CaO
2. BaO
3. BeO
4. MgO

Ans. (C) BeO

Explanation: BeO has both basic and acidic properties. Beryllium is the only alkaline earth metal that is insoluble and non-reactive in water. Because the size of this element is small and ionization energy is high relative to other elements of the group.

Ques 8. Which of the below-mentioned alkali metals has the lowest melting point?

1. K
2. Na
3. Li
4. Cs

Ans. (D) Cs

Explanation: The size of the metal is inversely proportional to the strength of its metallic bonding. As the size of the metal increases, metallic bonding decreases and vice-versa. As the size of Cs is the biggest, its melting point is the lowest.

Ques 9. Be shows a diagonal relationship with which of the following elements?

1. Al
2. Na
3. Mg
4. K

Ans. (A) Al

Explanation: Be and Al are placed in the second and third periods of the periodic table respectively, displaying a diagonal placement. They have similar ionic sizes and charge ratios. Both metals exhibit tendency to form covalent bonds.

Ques 10. Which of the below-mentioned alkali metals forms hydrated salts?

1. Li
2. Rb
3. Fr
4. K

Ans. (A) Li

Explanation: Lithium is the smallest in size amongst the alkali metal ions. Thus, it exhibits the highest charge density. And attracts the water molecules strongly compared to other alkali metal cations.

Ques 11. Which of the following metals is the flash bulb wire made of?

1. Ra
2. Sr
3. Ba
4. Mg

Ans. (D) Mg

Explanation: Mg filaments are used in bulbs filled with oxygen gas. These filaments react with oxygen to form a compound called Magnesium Oxide (MgO). The bright white light is a result of this exothermic reaction. Upon ignition, Mg releases a lot of heat in the form of light.

Ques 12. Which one of the below-mentioned carbonates has the most stability?

1. Barium Carbonate
2. Magnesium Carbonate
3. Calcium Carbonate
4. Beryllium Carbonate

Ans. (A) Barium Carbonate

Explanation: Moving down the periodic table, the electro-positiveness of the alkaline earth metals increases. Consequently, the thermal stability also increases. As the positive ions get bigger down the periodic table, their effect on the near carbonate ion declines. Thus, Barium Carbonate has the most thermal stability.

Ques 13. Which superoxide of the following alkali metals is used as an air purifier in spacecraft?

1. Na
2. K
3. Rb
4. Fr

Ans. (B) K

Explanation: Potassium Peroxide is used in the oxygen cylinders of the spacecraft. As it absorbs Carbon Dioxide and releases pure Oxygen at high altitudes. Thus, purifying the air.

Ques 14. Why does bleaching powder lose its efficiency in the long term?

1. Absorption of moisture      
2. It transforms into calcium hypochlorite
3. It transforms into calcium chloride and calcium hydroxide
4. It transforms into calcium chloride and calcium chlorate

Ans. (D) It transforms into calcium chlorate and calcium chloride

Explanation: Bleaching powder is unstable and long-standing reduces its chlorine content. Due to auto-oxidation, it transforms into calcium chlorate and calcium chloride.

Ques 15. Which of the following magnetic properties do alkaline earth metals exhibit?

1. Paramagnetic
2. Anti-Ferromagnetic
3. Diamagnetic
4. Ferromagnetic

Ans. (C) Diamagnetic

Explanation: The absence of unpaired electrons and noble gas configuration makes alkaline earth metals diamagnetic.

This set of Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “s-Block Elements – Anomalous Properties of Lithium”.

1. Lithium and magnesium are ____________ metals.
a) sponge
b) hard
c) soft
d) smooth

Answer: b
Explanation: Lithium and magnesium are harder than other metals in the group because they have a strong metallic bond among themselves. This is one of the similarities between Lithium and magnesium having a diagonal relation.

2. Lithium chloride is ____________ in nature.
a) soft
b) covalent
c) ionic
d) complex

Answer: b
Explanation: Both lithium chloride (LiCl) and magnesium chloride (MgCl) are predominantly covalent when compared to other elements in their respective groups, that is alkali metals and alkaline earth metals.

3. What is the difference between the Ionic radius of cations of Lithium and magnesium?
a) 2 A°
b) 0.05 A°
c) 1 A°
d) 5 A°

Answer: b
Explanation: The Ionic radius of Lithium cation is 0.60A°, which is very close to that of magnesium cation that is 0.65A°, therefore the difference between the Ionic radius of cations of Lithium and magnesium is 0.05A°.

4. What is the electronegativity of lithium?

a) 2
b) 1
c) 5
d) 4

Answer: b
Explanation: Electronegativity of Lithium is 1.0 and the electronegativity of magnesium as 1.2, they have almost similar electronegativities which is one of the reasons for Lithium and Magnesium’s diagonal relationship.

5. Which of the following statements is true regarding the diagonal relationship between Lithium and magnesium?
a) Lithium and magnesium combined with oxygen to form superoxides
b) Lithium and magnesium are soft metals
c) Lithium hydroxide and magnesium Hydroxide are weak bases
d) Magnesium chloride is completely soluble in water

Answer: c
Explanation: The correct statements of the incorrect ones are that; Lithium and magnesium combine with oxygen in order to form monoxides, they are hard metals and magnesium chloride is partially soluble in water as lithium chloride.

6. Which of the following element has the smallest size in its group?
a) sodium
b) rubidium
c) potassium
d) lithium

Answer: d
Explanation: The element Lithium whose atomic number is given by 3 is the smallest element in its group that is alkali metals by size. This is one of the reasons why it has anomalous behavior in the periodic table comparatively.

7. Does Lithium react with nitrites?
a) yes
b) no
c) may be
d) may not be

Answer: a
Explanation: Yes, Lithium which is unlike the other alkali metals, reacts with nitrogen to form the nitride six moles of lithium combine with one mole of a nitrogen atom, in order to form two moles of lithium nitride.

8. On heating lithium carbonate decomposes in order to evolve the ____________
a) nitrogen
b) oxygen
c) carbon dioxide
d) lithium

Answer: c
Explanation: Lithium carbonate decomposes on heating in order to avoid carbon dioxide whereas other alkali metal carbonates do not evolve carbon dioxide, this occurs because lithium carbonate is unstable in the presence of heat and is the least stable among the carbonates of alkali metals.

9. Lithium has a diagonal relationship with ____________
a) magnesium
b) sodium
c) aluminum

Answer: a
Explanation: Lithium shows diagonal resemblance with magnesium which is an element of group 2 and this resemblance is due to the similar polarising power of both these elements. polarizability is proportional to the ionic charge / the square of the Ionic radius.

10. Lithium has the same radius that of magnesium.
a) true
b) false

Answer: b

Explanation: The atomic radius of Lithium is 1.31Ao while that of magnesium is 1.34Ao, though Lithium and magnesium do not have the same radius, they have a similar radius which is a reason for their diagonal relationship.

This set of Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “s-Block Elements – Group 1 Elements: Alkali Metals”.

1. Which of the following metal is not an alkali metal?
a) magnesium
b) rubidium
c) sodium
d) caesium

Answer: a
Explanation: Alkali metals are the elements of group 1. The outer shell configuration of group 1 elements is ns1, where n is the number of it’s period. Magnesium is not an alkali metal because it’s outer shell configuration is ns2.

2. Alkali metals have the biggest atomic radii.
a) true
b) false

Answer: a
Explanation: The alkali metals have the biggest atomic radii in their respective periods, atomic radii increases as we go down the group due to the addition of a new shell in each subsequent step. So the above statement is true.

3. The melting point of alkali metal is _____________
a) depends on the atmosphere
b) low
c) high
d) zero

Answer: b
Explanation: The melting and boiling points of alkali metals are quite low and they decrease down the group due to weakening of their metallic bonds. Francium is the only element in this group which is a liquid at room temperature.

4. Is there removal of second electron difficult in alkali metals?

a) Yes
b) No
c) Maybe
d) Cannot say

Answer: a
Explanation: The first ionization enthalpy of alkali metals is the lowest among the elements in their respective periods and increases on moving down the Group. The second ionization enthalpies of the alkali metals are very high because by releasing an electron, ions require noble gas configuration, so removal of the second electron is difficult.

5. Alkali metals are strongly _____________
a) neutral
b) electropositive
c) electronegative
d) non-metallic

Answer: b
Explanation: Due to low ionization enthalpies, alkali metals are strongly electropositive or metallic in nature and electropositive nature increases from Lithium to caesium due to decrease in ionization enthalpy.

6. Alkaline earth metals show +1 Oxidation state and their atomic volume _____________ down the group.
a) is irregular
b) increase
c) decrease
d) do not change

Answer: c
Explanation: The alkali metal atom show only +1 Oxidation State, because of their unipositive Ion at the time the stable noble gas configuration. The atomic volume of alkali metals is the highest in its period and goes on increasing down the group from top to bottom.

7. Does the degree of hydration depend upon the size of the cation?
a) Yes
b) No
c) Maybe
d) Cannot say

Answer: a
Explanation: The degree of hydration depends upon the size of the cation, smaller the size of the cation, greater is its hydration enthalpy. The relative degree of hydration in an increasing order is Li+ > Na+ > K+ > Rb+ > Cs+.

8. The flame of caesium is in the colour _____________
a) white
b) red violet
c) yellow
d) blue

Answer: d
Explanation: Alkali metals and their salt impart characteristic colours to the flame because the outer electrons get excited to higher energy levels. When the electrons return to the original state, it releases visible light of a characteristic wavelength which provides colour to the flame. The colour of the Flame of the caesium is blue.

9. Caesium has the highest electrical conductivity in its group.
a) true
b) false

Answer: a
Explanation: Due to the presence of loosely held Valence Electrons which are free to move throughout the metal structure, the alkali metals are good conductors of heat and electricity. Electrical conductivity increases from top to bottom in the order, so caesium has the highest electrical conductivity in its group.

10. All alkali metals are good dash agents?
a) oxidizing
b) reducing
c) both oxidising and reducing
d) neither oxidizing not reducing

Answer: b
Explanation: All the alkali metals are good reducing agents due to their low ionization energies. The reducing character of group 1 elements follows the increasing order of Sodium, Potassium, rubidium, Caesium and lithium.

11. What happens when alkali metals are exposed to moist air?
a) formation of nitrates
b) formation of oxides
c) formation of chlorides
d) formation of sulphates

Answer: b
Explanation: On exposure to moist air, the surface gets tarnished due to the formation of oxides, hydroxide and carbonates. Few examples are sodium hydroxide, sodium carbonate, potassium hydroxide etc.

12. Sodium Peroxide is _____________ in colour and potassium superoxide is used as a source of _____________
a) blue, yellow
b) yellow, hydrogen
c) blue, oxygen
d) yellow, oxygen

Answer: d
Explanation: Sodium Peroxide acquires yellow colour due to the presence of superoxide as an impurity. Potassium superoxide is used as a source of oxygen in submarines, space shuttles and an emergency breathing apparatus such as oxygen masks.

13. Which of the following is true regarding the reactivity order of alkali metals towards hydrogen?
a) Li < Na < K > Rb
b) Lithium < Na < K < Rb < Cs
c) Li > Na < Cs
d) Li < Rb > Cs

Answer: b
Explanation: Two moles of alkali metal reacts with one mole of hydrogen molecule in order to form 2 moles of alkali metal hydride. The correct order of reactivity of alkali metals towards hydrogen is Li < Na < K < Rb < Cs.

14. Lithium fluoride is _____________ in water.
a) completely soluble
b) soluble
c) insoluble
d) cannot say

Answer: c
Explanation: All alkali halides except Lithium fluoride are soluble in water, this is because Lithium fluoride is soluble in nonpolar solvents as it has a strong covalent bond. Lithium fluoride is represented by the formula LiF.

15. Alkali metals dissolving in Ammonia liquid give the blue solution, this is due to the formation of ammoniated _____________
a) ions
b) metal cations only
c) metal cations and electrons
d) electrons only

Answer: c
Explanation: They give deep blue solution due to the formation of ammonia the metal cations and electrons, the blue colour is due to the oxidation of ammonia electron to higher energy levels and the absorption of photons occurs in the red region of the spectrum.