The half life of radon-222 is 3-5 days. how much of a 100grams sample is left after 15-20 days​

let that person have a turn to speak : )

i do not get it   at all

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.