Need if a chlorine atom were to gain one more electron, it would be similar to but not exactly the same as select one: a. argon b. bromine c. sulfur d. fluorine

- The correct answer is choice A, Argon.

Explanations:- Atomic number for chlorine atom is 17 means it has 17 electrons. If it gain one more electron then there becomes total 18 electrons.

Argon is next to chlorine and it's atomic number is 18 means it has 18 electrons. Chlorine ion and Argon atom has equal number of electrons means chlorine ion would be similar to Argon but not exactly the same as there is a difference of charge and number of protons.

the answer is b & c i believe : )