Why does ionization energy decrease down a group?

Related questions

1. How many kcal are in a kg?
2. Is kJ the same as KCAL?
3. How do you convert kJ mol to J photon?
4. How many kilocalories are in a kilo?
5. Is second ionization energy larger than first?
6. Does kJ or kcal count?
7. How many kJ Do I need to maintain weight?
8. What is a KCAL vs calorie?
9. What's the difference between kJ and KCAL?
10. What is the relationship between calories kilocalories and joules?

Tags

1. #factor
2. #period
3. #ionize
4. #increases
5. #easier
6. #energy
7. #moving
8. #valence
9. #ionization
10. #shielding
11. #group
12. #another
13. #number
14. #affects
15. #shell
16. #electron
17. #result
18. #decreases
19. #right
20. #strength
21. #electrons