Electrons in an atom or compound, ground state Electrons in an atom or compound, excited state Energy In, HEAT for example 1 2 3 4 1.Matter is in the ground state normally 2.Energy is inserted, here by heating 3.The atoms or atoms in compounds become excited by the gained energy 4.The electrons are unstable in the excited state, so they return to the ground state, giving off that energy they previously absorbed, as visible – colorful light (spectra) Energy Out 4
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