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Four Trends to Understand Atomic radius Ionization Energy Energy required to remove an electron from a gaseous atom or ion. Electron Affinity Energy change associated with the addition of an electron to a gaseous atom or ion. Electronegativity Ability of an atom in a molecule to attract shared electrons to itself.

IE vs. Atomic Number

Successive IEs

EA vs. Atomic Number

Clicker Question Given that the ionization energy of Si(g) = 780 kJ/mol and that the electron affinity of Si(g) = –134 kJ/mol, determine the ionization energy of Si–(g). a) 646 kJ/mol b) –646 kJ/mol c) 134 kJ/mol d) –780 kJ/mol e) The ionization energy of Si– cannot be determined with these data.

Clicker Question Given that the first two ionization energy values for Rb(g) = 403 kJ/mol and 2633 kJ/mol, respectively, determine the electron affinity of Rb(g).   a) –403 kJ/mol b) –2230 kJ/mol c) –2633 kJ/mol d) –3036 kJ/mol e) The electron affinity of Rb(g) cannot be determined with these data.

Electronegativity