I believe it is ice cubes.
Electronic configuration is given by

- 1s orbital is filled
- 2s orbital is unfilled
So
The first two ionization energy of nickel are expressed as:
Ni(g) = Ni^+(g) + e^- Ni^+(g) = Ni^2+(g) + e^-
IOnization energy os the energy that is neccessary in order to remove one mole of electrons from an atom.
Hope this helps.
These metallic substances are actually metal salts, which produce luminescent light of different colors when they are dispersed in the air. This light is produced by electrons inside the metal atoms
Hope this helped!