Which would least strongly attract electrons from other atoms in a compound?

The concept we are looking for here is electronegativity. This concept is a measure of how strong an atom or element can attract a pair, that is bonding, of electrons to itself. 

Fluorine is the element or atom of the greatest electronegativity. Electronegativity would increase as we move left to right of the periodic table. 

 

The gas would begin to expand, and eventually the can would burst or explode.

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