Question

Assertion: Catenation is the ability of an atom to form bonds with other atoms of the same element. It is exhibited by both carbon and silicon.
Reason: Carbon exhibits catenation much more than silicon or any other element due to its smaller size which makes the $C - C$ bonds strong while the $Si - Si$ bonds are comparatively weaker due to its large size and therefore, $Si$ does not have enough bond strength to hold together large molecules.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

This question gives the knowledge about the catenation. Catenation is the important property of an element. It allows an element to bind with itself to form ring (cyclic) molecules or chain molecules through covalent bonds.

Complete answer:
- Catenation is the important property of an element. It allows an element to bind with itself to form ring (cyclic) molecules or chain molecules through covalent bonds. . Catenation is most commonly preferred by carbon as it can easily form cyclic molecules such as benzene or long hydrocarbon chains. Catenation is exhibited by carbon because it contains four electrons in its valence shell. So, it is very difficult to gain four electrons because it will not be easy for nucleus to hold electrons. Also, it is very difficult for them to lose four electrons because a huge amount of energy will be required for this process.
- Same is the case for silicon. It also contains four electrons in its valence shell. So, it is very difficult for silicon also to gain four electrons because it will not be easy for nucleus to hold electrons. Also, it is very difficult for silicon to lose four electrons because a huge amount of energy will be required for this process.
- The catenation power generally decreases down the group.
Therefore, from the above explanation we conclude that both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

Hence, option B is the correct option.

Note: Always remember the concept that catenation is the property of an element which allows an element to bind with itself to form ring molecules or chain molecules through covalent bonds. Catenation is most commonly preferred by carbon.