1. b) Cl or Br
2. a) Li or K
3. Top to bottom: increases / Left to Right: decreases
4. c) F, K or V
5. Positive ions are smaller than the neutral atom it comes from, negative ions are larger than the neutral atom it comes from.
6. a) Na⁺, Na²⁺
7. It is the energy required to remove a single valence electron from an atom.
8. First ionization energy is the energy required to remove a single valence electron from an atom.
9. a) Mg, Na, Si
10. d) Cl, S
11. Decreases going right to left, decreases going down
Parent Tip: Review the logic above to help your child master the concept of worksheet periodic table trends answer key.