Excited States and Ground States

Key Questions

  • The ground state describes the lowest possible energy that an atom can have.

    Atoms may occupy different energy states. The energy states are discrete, i.e. they occur at specific values only. Therefore an atom can only move to a new energy level if it absorbs or emits an amount of energy that exactly corresponds to the difference between two energy levels.

    The lowest possible energy level that the atom can occupy is called the ground state. This is the energy state that would be considered normal for the atom.

  • An excited state is an energy level of an atom, ion, or molecule in which an electron is at a higher energy level than its ground state.

    An electron is normally in its ground state, the lowest energy state available. After absorbing energy, it may jump from the ground state to a higher energy level, called an excited state.