Answer:
The hydrogen molecules combine with the oxygen molecules, 2 hydrogen molecules, and 1 oxygen molecules is the amount needed to make one water atom or molecule, whatever you want to call it.
10 down: Particle with no charge
Answer: Neutron
20.181 u
The average atomic mass of Ne is the <em>weighted average</em> of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its % abundance).
Thus,
Avg. at. mass
= (0.904 83× 19.992 u) + (0.002 71 × 20.994) + (0.092 53× 21.991 u)
= 18.0894 u + 0.0569 u + 2.0348 u = 20.181 u
Ionic crystals are hard because of tight packing lattices, say, the positive and negative ions are strongly attached among themselves.
