Which of these atoms is most likely to share electrons with other atoms?

your question is incomplete as the options are not given. I guess following is the complete question.

Which of these atoms is most likely to share electrons with other atoms?

a) chlorine (7 valence electrons)

b) calcium (2 valence electrons)

c) argon (8 valence electrons)

d) carbon (4 valence electrons)

e) potassium (1 valence electron)

The correct option is d) carbon (4 valence electrons)

Explanation:

Carbon has four electrons in its valence shell. In order to complete the 8 electrons in its valence shell carbon has to make four covalent bonds by sharing its four electrons with the other atom. Carbon atom will neither gain the electrons nor it losses the electrons to follow the octet rule. So in the above mentioned options carbon is the atom that will share maximum electrons.

→ Chlorine has 7 electrons, it will gain 1 electron. It will not do the sharing.

→ Calcium has 2 electrons, it will lost these 2 electrons to complete its shell.

→ Argon has already a completed shell. It will not react with other atom.

→ Potassium has only 1 valence electron which it will lose to complete its shell.