Question

The total energy of an electron in an atom is
A.>0
B.<0
C.=0
D. Anything

Answer 1

d.anything because when we heat at extream temperature then bond will break and electron will be fully controlled by nucleus

Answer 2

Energy values are always given relative to some reference. In the case of atoms, the typical reference (set to zero) is the state where one electron is removed from the atom and taken infinitely far away. The atom with its electron is more stable than this ionized reference state, hence its energy is lower than the reference state energy (taken as zero) hence its energy is negative.