Which of the answer choices accurately describes a trend that occurs when moving left to right across periods?

Question

Select all that apply.

1 atomic mass increases
2 atomic radius increases
3 reactivity increases
4 valence electrons decrease
2 and 3?

Answer 1

2 is ok.
Think about 3. Does Mg have more reactivity than Na. Does Ca have more reactivity than K?
Think about 1. Except for a few hitches, doesn't atomic mass increase?