Answer: 
atoms of hydrogen are there in
35.0 grams of hydrogen gas.
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
1 mole of hydrogen 
= 
atoms
17.5 mole of hydrogen = 
atoms
There are atoms of hydrogen are there in
35.0 grams of hydrogen gas.
Ionization energy is the energy required to remove the
outermost electron from one mole of gaseous atom to produce 1 mole of gaseous
in to produce a charge of 1. The greater the ionization energy, the greater is
the chance f the electron to be removed from the nucleus. In this casse, Radium
has the largest ionization energy.
I would say that you should wear a lab coat, safety goggles, and gloves
when the teacher says so - not everything in a lab is dangerous, so
there is no need to always wear these. But when the teacher says you
should - then you should.
