Question

Which of the following processes involves absorption of energy and why?
a) Cl --> Cl-
b)O- --> O2-
c) O+ --> O-
d) S --> S-

Answer 1

i think it is a because cl is a noble gas and invovles abdorption of energy

Answer 2

Answer: Option (c) is correct.

Explanation:

In case of $O^{+} \rightarrow O^{-}$,

The electronic configuration of $O^{+}$ is $1s^{2}2^{2}2p^{3}$ and as the p sub shell is half filled, it will be stable.

Therefore, in order to become $O^{-}$, more energy needs to be provided. Hence, conversion of $O^{+} \rightarrow O^{-}$ will involve absorption of energy.

In case of $O^{-} \rightarrow O^{2-}$, the electronic configuration of $O^{-}$ will be $1s^{2}2^{2}2p^{5}$. Therefore, in order to complete the octet $O^{-}$ will readily accept an electron. Hence, there will be release of energy.

Whereas, the size of chlorine is large so it will readily lose an electron to become $Cl^{-}$ so there will be release of energy.

Similarly, the size of sulfur is large as compared to oxygen so, it will readily lose an electron to become $S^{-}$. Hence, there will be absorption of energy.

Thus, it can be concluded that the conversion of $O^{+} \rightarrow O^{-}$ involves absorption of energy.