<span>Density is a value for
mass, such as kg, divided by a value for volume, such as m3. Density is a
physical property of a substance that represents the mass of that substance per
unit volume. We calculate as follows:
PV = nRT
PV = mRT/ Molar mass
m/V = P(molar mass)/RT
Density = P(molar mass)/RT
Density = 2.0 ( 30.97 ) / 0.08206 ( 20 + 273.15) = 2.57 g/L <----First option</span>
They have same chemical properties
for example the elements of group VIII are called noble gases .They are unreactive, odorless and colorless.
add up the mass of protons and neutrons
Well, these particles happens to be small, like REALLY small. So microscopically small they aren't picked up or observed my the naked eye. also the vibrations are in an atomic scale which is also VERY tiny This goes for all solids too.
