CHEM 130 Lecture Notes - Lecture 9: Ionic Bonding, Electron Shell, Noble Gas
Document Summary
Clicker: the following graph plots the 1st, 2nd, and 3rd ionization energies for 3 different elements. Why: the rst ionization energy takes ca > c+ removing 3s, the second take ca+ > ca2+ removing 3s, 3rd c2+ to ca3+ removing a 2p (much closer to electron so much harder to remove) Electron a nity: the energy change associated with addition of an electron to a gaseous atom x(g) + e- > x-(g: positive or negative energies, usually negative but can be positive. If it leads to a more stable system it is going to be negative. If it leads to less stable (electron repulsion stronger) then you are going to get positive. Across a period: ea becomes more negative/ more stable (zeff increases, more positive charge, easier to add an electron to that system) Down a group: ea becomes more positive (distance between electrons and nucleus increases) Note: not larger or smaller, it is more negative or more positive.
