How do the elements in the noble gas family compare?

Noble gases are the most stable chemical elements because they have completely filled valence shells containing the maximum number of electrons it can hold. Noble gases forms Group 18 in the modern periodic table. The order down the periodic table is as follows:

helium (He)

neon (Ne)

argon (Ar)

krypton (Kr)

xenon (Xe)

radon (Rn)

oganesson (Og)

Comparison:

The atomic mass increases as we move down the column because the number of neutrons and protons increase.

The melting and boiling points of the noble gases increases down the group. The reason is that the size of the atom increases downwards. Noble gases have London Dispersion Forces between them. As the dispersion increases, the London Dispersion Forces have more chances of forming a bond. Stronger bonds down the group means higher melting and Boiling points.

Similarly, the density of noble gases increases down the group as stronger forces are there between atoms.

The ionization energy decreases down the group of Noble gases because the electrons in bigger noble gases are located away from the nucleus and held less tightly by the atom.

Compared to other elements, Noble gases have low Melting and Boiling points.  

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

increase masses, decrease separation