-Chemistry Help- 24PTS!

Fill in the Blank
1.) There are three known forms of hydrogen. These forms are called ------- of each other. Each of these forms will have the same number of -----but different numbers of ---- in their nuclei.

2.) Periods on the periodic table represent elements_____.

Select all that apply.
with the same number of valence electrons
with increasing number of valence electrons
with the same number of electron orbits
with increasing atomic size