The atomic # and the mass #.
Atoms can be the source of both nuclear and chemical energy. Nuclear energy involves the atom's nucleus; chemical energy involves the atom's electrons—subatomic particles that surround the nucleus.
Attraction between polar molecules
Space -filling models are also known as Calotte models. These are 3 dimensional models that depict the spatial relationships between atoms.
The space-filling model of water molecule shows the 3 D structure of the water molecule. This model CLEARLY REVEALS THE OXYGEN ATOM WHICH IS LOCATED CENTRALLY WITH TWO HYDROGEN ATOMS IN THE ADJACENT SIDES. THE MODEL ALSO SUGGESTS HOW THE WATER MOLECULES ATTRACT EACH OTHER.
N₂O
N = 14.01 amu
O ≈ 16 amu
14.01 × 2 = 28.02 ; 2 Nitrogen
44.02 - 28.02 = 16 ; 1 Oxygen
Check
28.02 + 16 ≈ 44.02amu