A-Level chem- ionisation energy and electrons

the 5th IE of carbon is exceptionally high, which shows carbon becomes stable after losing 4 electrons. So Carbon is group 4.

flame test:

in room temperature, all atoms are in ground state. In a flame, electrons absorb energy and are promoted to a higher energy level. The high enery level is unstable, and soon the electron drop to a lower energy level, emitting a photon. If the wavelength of the photon is witihin the visible light spectrum, we can see coloured flame.