Periodic Table Trends • Atomic Radii- size of the atom • Ionic Radii – size of the ion • Electronegativity- tendency to attract electrons to itself when chemically combined with another element. • Ionization Energy- energy required to remove an electron first ionization energy - remove 1 electron second ionization energy - remove 2 electrons
Important things that use trends • Coulomb’s Law • Photoelectric Spectroscopy
Coulomb’s Law • Describes the attractions and repulsions between charged particle • E = (q1q2)/ r • E is potential energy • q is charge of ion • R is radius
Like charges, E is positive…when the r increases the E goes down. • System goes towards lower potential energy, more distance between particles = lower energy…Like repels like • Opposite charges, E is negative…when r decreases the E gets more negative. • Lots of attraction • Small size and large opposite charges give the best columbic attraction (or lattice energy).
Photoelectric Spectroscopy • Plots number of electrons vs ionization energy of the electrons…or how much energy it takes to strip an electron away from an element. • You will need to remember electron configuration …1s²2s² • S = 2 e- p = 6 e- d= 10 e- f= 14 e- • Shells are happy ½ filled or fully filled • When electrons are in the same sub orbital e- pair repulsion makes it easier to take away one of the e-.