1. How is the electron configuration of an element determined? How do you know how
many valence electrons an element has? (You may use nitrogen as an example
element if it helps you explain.)

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

Maybe you should get some from your teacher and learn more so you can get your grades up and maybe study a bit more