Which element will gain one electron in an ionic bond? Select one:
a. Al
b. Cu
c. Br
d. O

C. Bromine

Explanation:In ionic bond , the metals looses electron and the non metal gains electron.

In the given options ;

Aluminum (Al)= METAL

Copper (Cu) = METAL

Bromine (Br) = NON METAL

Oxygen (O) = NON METAL

That leaves us with bromine and oxygen.

Oxygen has an electronic configuration of 2,6.(see image).

So oxygen needs to gain two electrons.

Bromine has one valence electron ( see image).

So therefore , Bromine needs to gain one electron as It is in Group VII

The answer is true for your question.

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na