Atoms are no longer indivisible and consist of electrons, protons, neutrons and even more sub-particles. Atoms of the same element may differ from one another called isotopes. Atoms of different elements may be similar called isobars.   Energy levels are areas located at fixed distances from the nucleus of the atom. They are the only places where electrons can be found. Energy levels are little like rungs on a ladder. You can stand on one rung or another but not between the rungs. The same goes for electrons. They can occupy one energy level or another but not the space between energy... Show more

Atoms are no longer indivisible and consist of electrons, protons, neutrons and even more sub-particles. Atoms of the same element may differ from one another called isotopes. Atoms of different elements may be similar called isobars.
 

Energy levels are areas located at fixed distances from the nucleus of the atom. They are the only places where electrons can be found. Energy levels are little like rungs on a ladder. You can stand on one rung or another but not between the rungs. The same goes for electrons. They can occupy one energy level or another but not the space between energy levels. The level with the least energy is the one closest to the nucleus, or n = 1. As you go farther from the nucleus, the levels have more and more energy.    

Electrons can jump from one energy level to another. If an atom absorbs energy, some of its electrons jump to a higher energy level. When the electrons jump back to the lower energy level, the atom emits, or gives off, energy.    
Energy levels explain fireworks. When chemicals in fireworks explode, their atoms absorb energy and some of their electrons jump to a higher energy level. When the electrons jump back to their original lower energy level, the atoms give off energy as light. Different chemicals have different arrangements of electrons and give off light of different colors.    

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