Some electron affinities are negative quantities, while some are zero or positive. Why is this not also the case with ionization energies? Electron affinities use a different reference point for where "zero" energy is defined. lonization energies are always positive because separating a negatively charged electron from a positively charged nucleus or cation will always require energy, as these particles will

The electron volt (eV) is a convenient unit of energy for expressing atomic-scale energies. It is the amount of energy that an electron gains when subjected to a potential of 1 volt; 1eV=1.6021019 J. Using the Bohr model, determine the energy, in electron volts, of the photon produced when an electron in a hydrogen atom moves from the orbit with n=5 to the orbit with n=2. Show your calculations.

r Questions 11—13, you will need to consider ionizations beyond the first ionization energy. For example, the second ionization energy is the energy to remove a second electron from an element. Compare the first ionization energy of helium to its second ionization energy, remembering that both electrons come from the 1s orbital. l> X Y First 170 200 second 350 400 Third 1800 3500 fouth 2500 5000 entify the elements X and Y. There may be more than one answer. so explain completely.

Write the valence-electron configuration of each of the following elements, basing your answer on the element’s location on the periodic table. uranium, Z=92 c. mercury, Z=80 manganese, Z=25 d. francium, Z=87