4. Chemists can identify the composition of some unknown salts by conducting a flame test. When potassium salts are heated in a flame, a purple color is observed. This is due to the movement of electrons between energy levels. What is the electron configuration of a potassium atom at ground state? (A) 1s°2s²2p°3s?3p°4d! (B) 1s22s²2p°3s²3p°3d! (C) 1s²2s?2d63s²3d°4s' (D) 1s°2s²2p°3s?3p°4s! In a 3.7-gram sample, there are (A) 1.1 x 1022 atoms of gold (B) 3.2 x 1025 atoms of gold (C) 4.4 x 1026 atoms of gold (D) 3.1 x 10-26 atoms of gold 5. atoms of gold (Au). 6. Which total mass is the largest? (A) The mass of 2 electrons (B) The mass of 2 neutrons (C) The mass of 1 electron plus the mass of 1 proton (D) The mass of 1 neutron plus the mass of 1 electron

16) In qualitative terms, how does Bohr's model account for the atomic spectrum of hydrogen? More than one selection may be correct. a) When a hydrogen atom absorbs energy, as it does when an electric discharge passes through it, the electron stays in the orbit having n = 1. b) The energy released when an electron drops from a higher to lower orbit appears as a photon with the appropriate frequency. c) The energy released when an electron drops from a higher to lower orbit appears as a photon with energy equal to the energy difference between the two orbits. d) Electrons are found in orbits of arbitrary energy. e) The energy released when an electron drops from a higher to lower orbit appears as a photon with an arbitrary frequency. f) Electron moves around the nucleus along orbits. g) When a hydrogen atom absorbs energy, as it does when an electric discharge passes through it, the electron is raised from the orbit having n = 1 to a higher orbit, to n = 2 or n = 3 or even higher.

Identify the neutral element represented by this excited‑state electron configuration.   excited state: 1?2 2?2 2?6 3?2 3?0 4?1 Write the full ground‑state electron configuration for that element.

What is the wavelength of light (in nm) emitted when an electron transitions from n = 3 to n = 2 in a hydrogen atom? Submit an answer to three signficant figures.