Question

How many particles are there in a mole of nitrogen dioxide molecules? How many total atoms are there in a mole of nitrogen dioxide molecules?How many nitrogen atoms? How many oxygen atoms?

Answer 1

There are 6.02E23 molecules of NO2 in a mole of NO2. Since NO2 is a covalently bonded molecules that is the number of particles.
For N. You have 1 atom N for each molecule NO2; therefore, you have that many atoms N.
For O. You have 2 atoms O for each molecule NO2; theefore, you ave 2x that many atoms O.
The total is the sum of N atoms + O atoms.