5. Which statement is correct for atomic radii? O The largest atomic radius and smallest atomic radius are
found at low atomic masses.
O The largest atomic radius and smallest atomic radius are
found at high atomic masses.
O The largest atomic radius is found at high atomic masses,
and the smallest atomic radius is found at low atomic masses.
O The largest atomic radius is found at low atomic masses,
and the smallest atomic radius is found at high atomic masses.

The largest atomic radius and smallest atomic radius are

found at high atomic masses.

Explanation:

If the molecular formula is NH, then it means there are 1 molecule of nitrogen every 1 molecule of hydrogen. In this case, the hydrogen atomic mass is 1 and its weight is 0.0864 grams. The nitrogen weight 0.403 grams and we need to find the atomic mass. The calculation should be:

(1/ 0.0864 gram) * 0.403 = 4.66

I'm not sure that there is NH molecule. The molecular weight of nitrogen should be 14 so the question might be wrong. If the reaction is N2 + 3 H2 → 2 NH3 
Then the answer is: (3/ 0.0864 gram) * 0.403 = 14