Solved Practice Questions on Group 13 & 14 Elements: Boron and Carbon Family | Inorganic Chemistry PDF Download

Q.1. Are group 13 elements a part of p block elements?
(a) Yes
(b) No
(c) Only a few
(d) Only one

Correct Answer is Option (a)
The last electron enters in the outermost p-orbital in the p block elements, from group 13 to group 18 the entire elements belong to p-block, whereas group 13 is called a boron family. It includes the elements boron, aluminum, gallium, indium and thallium. 

Q.2. The ionization enthalpy and density increase in the group from top to bottom.
(a) true
(b) false

Correct Answer is Option (b)
Density increases with increase in atomic number due to the increase in mass per unit volume down the group and the ionization enthalpy decreases from carbon to stannum, for plumbum it is slightly higher than stannum. So the above statement is considered to be false. 

Q.3. Which of the following group’s elements have smaller atomic radii?
(a) Group 1 elements
(b) Group 2 elements
(c) Group 13 elements
(d) All have the same atomic radii

Correct Answer is Option (c)
Group 13 elements have smaller atomic radii and ionic radii than those of alkaline earth metals and alkali metals due to the greater effective nuclear charge, atomic radii increases on going down the group with an abnormality at gallium. 

Q.4. Why hydrides of Germanium are known as ______.
(a) silanes
(b) germanes
(c) stannum
(d) plumbane

Correct Answer is Option (b)
The hydrides of carbon are called hydrocarbons alkanes, alkenes or alkynes, whereas the hydrides of silicon are called silanes and the hydrides of germanium are called Germanes the only hydrides of stannane and plumbum are stand and plumbane. 

Q.5. The atomic radius of gallium is greater than that of aluminum.
(a) True
(b) False

Correct Answer is Option (b)
Though the atomic radii increase on going down the group, the radius of gallium decreases unexpectedly because of the presence of electrons in the orbitals which do not screen the attraction of the nucleus effectively. So the atomic radius of gallium is less than that of aluminium. 

Q.6. The group 14 elements form ______ hydrides.
(a) metallic
(b) ionic
(c) covalent
(d) both covalent and ionic

Correct Answer is Option (c)
All the members of group 14 form covalent hydrides, their number and ease of formation decreases down the group along with their thermal stability while their reducing character increases down the group. 

Q.7. Which of the following elements does not belong to the Carbon family?
(a) aluminium
(b) silicon
(c) plumbum
(d) stannum

Correct Answer is Option (a)
The elements of Carbon family are the elements of group 14. They are carbon, Silicon, Germanium, stannum and plumbum. Their valence shell configuration is ns²np² and their valency is four. But aluminium belongs to group 13. 

Q.8. Gallium remains liquid up to ______ Kelvin.
(a) 2176
(b) 2376
(c) 2476
(d) 2276

Correct Answer is Option (d)
Low melting point of gallium is due to the fact that it consists of Ga₂ molecules and gallium remains liquid up to 2276 k. Hence it is used in high-temperature thermometer. Gallium as a chemical symbol that is Ga and its atomic number is given as 31. 

Q.9. Which of the following group 14 elements is a metal?
(a) Stannum
(b) Carbon
(c) Germanium
(d) Silicon

Correct Answer is Option (a)
There are mainly five elements in carbon family; carbon, silicon, germanium, stannum and plumbum. The carbon and silicon are non-metals, germanium is a metalloid whereas stannum, plumbum are metals. 

Q.10. The ionization enthalpy ______ down the group in the family.
(a) Increases
(b) Decreases
(c) Constant
(d) Is a regular

Correct Answer is Option (d)
On moving down the group, ionization enthalpy decreases from Boron to aluminium, but the next element gallium has slightly higher ionization enthalpy than aluminium due to the poor shielding of intervening d-electrons, it again increases in indium and then decreases in the last element thallium. 

Q.11. What is the colour of silicon?
(a) blue
(b) silver
(c) black
(d) light brown

Correct Answer is Option (d)
One of the main general physical properties of group 14 elements is their colour. The colour of carbon is black, silicon is light brown, germanium is greyish, stannum is silvery white and plumbum is also silvery white in colour. 

Q.12. Inert pair affect ______ down the group.
(a) Increases
(b) Decreases
(c) Constant
(d) Is a regular

Correct Answer is Option (a)
Inert pair effect is the reluctance of the selections of the valence shell to take part in bonding, it occurs due to pore shielding of ns² electrons by intervening d-electrons and f-electrons, down the group, it increases. The below elements of the group exhibit lower oxidation States. 

Q.13. What is the fajan’s rule about?
(a) electronegativity
(b) ionic compounds
(c) Oxidation State
(d) covalent compounds

Correct Answer is Option (c)
The Fajan’s rule is that the compounds in +2 oxidation state are ionic in nature and + 4 oxidation state is covalent in nature, therefore the Fajan’s rule is about Oxidation state and their nature of the compounds. 

Q.14. Which of the following element exhibits + 3 Oxidation State only?
(a) Gallium
(b) Thallium
(c) Indium
(d) Aluminium

Correct Answer is Option (d)
Boron and aluminium exhibit oxidation state of + 3 only, while gallium, indium and thallium exhibit oxidation states of both +1 and +3. As we move down the group, the tendency to exhibit + 3 Oxidation State decreases this occurs due to the inert pair effect. 

Q.15. Do Carbon family elements show multiple bonding?
(a) Yes
(b) Maybe
(c) No
(d) Cannot say

Correct Answer is Option (a)
Yes, carbon forms pπ-pπ bonds with itself and with sulphur, nitrogen and oxygen other elements show the negligible tendency of this type due to their larger size. Other elements form dπ-pπ multiple bonds. 

Q.16. Which of the following is true regarding reducing character?
(a) Gallium < aluminium > indium > thallium
(b) Aluminium > gallium > indium > thallium
(c) Aluminium > gallium < indium > thallium
(d) Gallium > aluminium > indium > thallium

Correct Answer is Option (b)
Reducing character of the boron family decreases down the group from aluminium to thallium because of the increase in electrode potential value for M³⁺/M, therefore, the correct order is given as aluminium > gallium > indium > thallium. 

Q.17. All the elements in group 14 exhibit tetravalency.
(a) true
(b) false

Correct Answer is Option (a)
In the case of carbon, 406 KJ per mole of energy is required for promotion of 2s electron to 2p. The formation of two extra bonds provides this energy, therefore we can say that all the elements exhibit tetravalency in group 14. So the above statement is true. 

Q.18. Complex formation is more likely to be possible in ______.
(a) alkali metals
(b) alkaline earth metals
(c) boron family
(d) equally likely

Correct Answer is Option (c)
The complex formation in the boron family is greater than the S block elements due to their smaller size and greater charge. So they can form complexes more likely than alkali metals and alkaline earth metals. 

Q.19. Is catenation possible in carbon?
(a) Yes
(b) Maybe
(c) No
(d) Cannot say

Correct Answer is Option (a)
Catenation is a tendency of elements to form long chains with repeated units of the same element. The greater the strength of element, the greater the strength of catenation. In the carbon family, the catenation strength is in the decreasing order of carbon, silicon, germanium = stannum and plumbum. 

Q.20. The compounds formed by the Boron family are ______.
(a) ionic
(b) covalent
(c) both ionic and covalent
(d) neither ionic nor covalent

Correct Answer is Option (c)
Ionic compound formation’s tendency increases from Boron to thallium. Boron can only form covalent compounds, whereas aluminium can form both covalent as well as ionic compounds. Gallium forms mainly ionic compounds.