Why does electron affinity increase across a period?

Related questions

1. What is classification of elements?
2. Why does boiling point increase down Group 15?
3. Does boiling point increase across a period?
4. What is electron affinity trend?
5. Why does atomic radius increase down a group?
6. What are the merits of Mendeleev periodic table?
7. Why does the metallic character increase as you go down a group?
8. What is the trend for density on the periodic table?
9. Why does melting and boiling point increase down Group 7?
10. Which is more electronegative C or H?

Tags

1. #electron
2. #levels
3. #groups
4. #electrons
5. #across
6. #increases
7. #right
8. #table
9. #between
10. #because
11. #added
12. #attraction
13. #upward
14. #closer
15. #affinity
16. #stronger
17. #periodic
18. #energy
19. #periods
20. #nucleus
21. #become