An atom that has excess energy is called what?

• A. Isotope
• B. Radioactive atom
• C. Excited atom
• D. Neutral atom

Answer: (B)

Excess energy in an atom means the electrons have been promoted to higher energy levels, so the atom is in an excited state. This excited atom is not necessarily unstable in the nuclear sense; it’s simply carrying more energy in its electronic structure. When the energy is released, the atom typically returns to the ground state by emitting a photon, which is why excited states produce characteristic light spectra. This is different from radioactivity, which involves instability in the nucleus and radioactive decay over time. Isotopes refer to atoms of the same element with different numbers of neutrons, and a neutral atom has a balanced number of protons and electrons. So, the correct concept for an atom with excess energy is an excited atom.