When one observes the phase of matter of water, one observes a physical property of matter.
Boiling point ..................................................
The film which you called it is photographic film and it is strip like sheet and it's surface is clrear and transparent plastic which is coated on
two sided one side is with gelatin emulsion consists microscopic small light-sensor which is actually very sensitive in nature silver halides crystals. The size shape and other characters of the crystals gives the sensitivity,contrast of different colors combination ,and resolution of the films.
Ionization energy (IE) is the amount of energy required to remove an electron.
If you observe the IEs sequentially, there is a large gap between the 2nd and 3rd. This suggests it is difficult to remove more than 2 two electrons. Elements that lose two electrons to become more stable are found in the Group 2A (2 representing the number of electrons in the outermost valence shell).