Electron energies

 Electron energies

Electron Energies:

Each isolated atom has only a certain number of orbits available. These orbits represent energy levels for the electrons. Modern physics tells us that only discrete values of electron energies are possible. An electron cannot have any value of energy (usually expressed in eV*), but only certain permissible values.

No electron can exist at an energy level other than a permissible one.

The above figure shows the single atom have the different energy levels available for its electrons.

In an atom, an electron which is near the nucleus has low energy, and those electrons which are far from the nucleus have high energy. Means greater the distance from nucleus, greater the electron total energy, and close the distance form nucleus , low the electron total energy.

 

Electrons which are closest to the nucleus are called bound electrons have only a small amount of energy. It would be difficult to knock out this electron. On the other hand, an electron orbiting far from the nucleus would have greater energy, and hence it could easily be knocked out of its orbit. This is why it is the valence electrons .

 

Only valence electrons take part in chemical reactions and in bonding the atoms together to form solids.

 

When energy like heat, light or other radiations impinge on an atom, the energy of the electrons increases. As a result, they are lifted to higher energy levels (larger orbits). the atom is then said to be excited. This state does not last long. Very soon, the electrons fall back to the original energy level. In this process, the electron gives out energy in the form of heat, light or radiations.