Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Electrons are tiny, negatively charged particles in an atom that move around the positive nucleus at the center. Energy levels are a little like the steps of a staircase.

In a noble gas, an atom tends to have eight electrons in its outer shell (except helium, which is only able to fill its shell with two electrons)….Valence shell.

Atom Energy Shells or Levels The electron which rotates in the lowest orbit has lowest energy level and in the outermost orbit, electrons have higher energy levels. Hence energy levels increase as the distance from the nucleus increases. There are many shells around the nucleus which are arced as K, L, M; N, and so on.

The highest energy acquired by an electron is at K shell , and slowly energy decreases as one moves to L,M,N shells.

eight electrons
The innermost shell is filled first. This shell can contain a maximum of two electrons. The second shell can hold a maximum of eight electrons. When this is filled, electrons go into the third shell, which also holds a maximum of eight electrons….Electron shells.

Each atom is characterized by its electron configuration. The energy level diagram is used to represent the energy states available in each atom. When an electron is in an energy state, it emits nor absorbs radiation. A photon is emitted or absorbed when an electron transitions from one energy state to another.

two electrons

K shell
The lowest energy level (the K shell) can only be occupied by two electrons, the L shell by 8 and the M shell by 18. The K shell electrons are closest to the nucleus.

Electrons require a certain amount of energy to stay in an orbit. This particular quantity is called the electron’s energy level. By its motion alone, the electron possesses kinetic energy, while the electron’s position in orbit determines its potential energy.

Electron shells Energy shell Maximum number of electrons First 2 Second 8 Third 8

Orbital: A region of space within an atom where an electron in a given subshell can be found. Any orbital can hold a maximum of 2 electrons with opposite spin. The first shell has one 1s orbital and holds 2 electrons. The second shell holds 8 electrons; 2 in a 2s orbital and 6 in three 2p orbitals.

Shell (electron): A grouping of electrons in an atom according to energy. The farther a shell is from the nucleus, the larger it is, the more electrons it can hold, and the higher the energies of those electrons.

While electron shells and orbitals are closely related, orbitals provide a more accurate picture of the electron configuration of an atom. That’s because orbitals actually specify the shape and position of the regions of space that electrons occupy.