Solved Practice Questions on Group 1 & 2 Elements: Alkali and Alkaline Earth Metals | Inorganic Chemistry PDF Download

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

Correct Answer is Option (a)
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.

Q.2. Which of the following is not an alkaline earth metal?
(a) beryllium
(b) boron
(c) aluminium
(d) calcium

Correct Answer is Option (a)
Beryllium, belongs to the 2^nd group. It is not called as an alkaline earth metal because the first element of this group that is beryllium is different from the rest of the members and it also shows a diagonal relationship with aluminium. 

Q.3. Alkali metals have the biggest atomic radii.
(a) true
(b) false

Correct Answer is Option (a)
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. 

Q.4. How many electrons do group 2 elements have in their S orbital of the valence shell?
(a) 1
(b) 2
(c) 3
(d) 4

Correct Answer is Option (b)
The alkaline earth metals have two electrons in the s-orbital of their valence shell and their general electronic configuration as represented as ns². Similar to the alkali metals these elements compounds are predominantly ionic. 

Q.5. The melting point of alkali metal is ______.
(a) depends on the atmosphere
(b) low
(c) high
(d) zero

Correct Answer is Option (b)
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. 

Q.6. Which of the following order is correct with respect to the hydration enthalpy?
(a) B > Mg > Ca < Sr > Ba
(b) Be⁺² > Mg⁺² > Ca⁺² > Sr⁺² > Ba⁺²
(c) B > Mg < Ca > Sr > Ba
(d) B > Mg > Ca > Sr < Ba 

Correct Answer is Option (b)
The hydration enthalpy decreases with the increase in ionic size along with the group towards down, the correct order of hydration enthalpy is given as Be⁺² > Mg⁺² > Ca⁺² > Sr⁺² > Ba⁺² and the hydration enthalpies of alkaline earth metal ions are greater than the size of alkali metal ions. We can say that these are extensively hydrated than them. 

Q.7. Is there removal of a second electron difficult in alkali metals?
(a) Yes
(b) No
(c) Maybe
(d) Cannot say

Correct Answer is Option (a)
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. 

Q.8. What is the colour of barium?
(a) brick red
(b) crimson
(c) apple green
d) blue

Correct Answer is Option (c)
The colours of Barium, Strontium and Calcium are Apple Green, Crimson and brick red. These are the colours of their flames, the colours occur when an electron is excited and jumps into a higher energy level and then drop back. They emit the radiation in the form of visible light. 

Q.9. Alkali metals are strongly ______.
(a) neutral
(b) electropositive
(c) electronegative
(d) non-metallic

Correct Answer is Option (b)
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. 

Q.10. Powdered beryllium burns in order to give ______.
(a) barium sulphate
(b) beryllium chloride
(c) beryllium nitride
(d) beryllium hydride

Correct Answer is Option (c)
We know that beryllium is kinetically inert to Oxygen and water as it forms oxide film on the surface. But whereas powdered beryllium burns brightly on ignition in the air in order to give the oxides and nitrides of beryllium. 

Q.11. Alkaline earth metals show a +1 Oxidation state and their atomic volume ______ down the group.
(a) is irregular
(b) increase
(c) decrease
(d) do not change

Correct Answer is Option (c)
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. 

Q.12. Which of the following is the best route to prepare BeF₂?
(a) thermal decomposition of BeF₂
(b) thermal decomposition of beryllium
(c) thermal decomposition of (NH₄)₂BeF₄
(d) thermal decomposition of Barium sulphate 

Correct Answer is Option (c)
All the alkali Earth metals combine with halogen at elevated temperatures forming their halides, the thermal decomposition of (NH₄)₂BeF₄, is best road and to prepare BeF₂ and BeCl₂ is conveniently made from the oxide.

Q.13. Does the degree of hydration depend upon the size of the cation?
(a) Yes
(b) No
(c) Maybe
(d) Cannot say

Correct Answer is Option (a)
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⁺. 

Q.14. Can beryllium hydride be prepared by combining with hydrogen through Heating?
(a) Yes
(b) No
(c) Maybe
(d) May not be

Correct Answer is Option (b)
All the alkaline earth metals (except beryllium) their hydrides can be prepared by combining with hydrogen. We can prepare beryllium hydride, through heating beryllium chloride with lithium aluminium hydride. 

Q.15. The flame of caesium is in the colour _______.
(a) white
(b) red violet
(c) yellow
(d) blue

Correct Answer is Option (d)
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.

Q.16. The reduction potential of alkaline earth metals is _______ alkali metals.
(a) may be equal to
(b) greater than
(c) less than
(d) equal to

Correct Answer is Option (c)
Although the alkaline earth metals are reductants in nature, their reducing potential is not as greater as alkali metals. Beryllium has a negative value when compared to the other elements in its group, this is due to the large hydration energy associated with the small size of beryllium. 

Q.17. Caesium has the highest electrical conductivity in its group.
(a) true
(b) false

Correct Answer is Option (a)
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. 

Q.18. Which of the following is a component of milk of magnesia?
(a) magnesium oxide
(b) magnesium sulphate
(c) magnesium hydroxide
(d) magnesium chloride

Correct Answer is Option (c)
Suspension of magnesium Hydroxide in water is known as milk of magnesia and it is used as an antacid in order to treat acidity. It works as a strong base while magnesium carbonate is an ingredient and toothpaste. 

Q.19. All alkali metals are good dash agents?
(a) oxidizing
(b) reducing
(c) both oxidising and reducing
(d) neither oxidizing nor reducing

Correct Answer is Option (b)
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. 

Q.20. With which of the following elements magnesium does not form an alloy?
(a) manganese
(b) aluminium
(c) zinc
(d) barium

Correct Answer is Option (d)
Magnesium combines with few elements like aluminium, manganese, zinc and tin in order to form a lot of magnesium aluminium alloys which are very light in mass and are used in the construction of aircraft. There are also many other uses of magnesium. 

Q.21. 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

Correct Answer is Option (b)
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. 

Q.22. 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

Correct Answer is Option (d)
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. 

Q.23. 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

Correct Answer is Option (b)
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. 

Q.24. Lithium fluoride is ______ in water.
(a) completely soluble
(b) soluble
(c) insoluble
(d) cannot say

Correct Answer is Option (c)
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. 

Q.25. 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

Correct Answer is Option (c)
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.