Question

What is a quantized atom?

Answer 1

This is a bit of a strange question. An atom is an atom, but we apply a theory called quantum theory to it to explain the observed phenomena. This theory states that the energy levels of the electrons in the atom can have only discrete (or quantised) values. This is analogous to them only being permitted to orbit at certain discrete distances from the nucleus. If we compare it to teh solar system, it would be like saying that Earth could only orbit the sun at the distance of mercury, venus, earth, or mars (or any other planet), but was not allowed to orbit at any point between). Hence there is a quantisation of allowed orbits, as opposed to a continuum.