what arrangement of electrons in distinct energy levels is based on a) scattering experiences, c) atomic spec?

Question

a) scattering experiments b) photo electric studies c) atomic spectra, d) radioactivity

Answer 1

This appears to be a paraphrasing of a multiple choice test question. I re-paraphrase the question: "What kinds of experiments are relevant to the theory that the arrangement of electons in an atom are associated with distinct energy levels?"
A) Scattering experiments in the early 1900s demonstrated that the region of space occupied by the nucleus of an atom was extremely small. Most particles beamedf at a thin film of gold pass through and only vary small number are scattered when they strike the nucleus of a gold atom. This was the first demonstration of the modern theory of the structure of atoms.
B) When light is shown upon a metal surface, some electrons are knocked out of or set free from the metal. This is the photo electric effect and although the energy levels are discreet (quantas) the better answer is choice C.
C) Atomic spectra experiments show that an element (hydrogen, nitrogen) can be identified by the unique wave lengths of light it emits when it is heated to high temperatures. Every element has a unique spectrum colors it emits as it gives up the energy that was given to it by, say, a bombarding particle.The colors tell what the arrangement of electrons in the substance is and thus identifies what element is being studied.This is how the composition of stars is determined.
D) Radioactivity is the energy emitted by an atom when the nucleus undergoes a structural change. These are nuclear reactions not directly related to the aarrangement of electrons in the region around the nucleus.