Periodicity

Periodic Properties Also called periodicity Properties associated with the periodic table Repetitious over the table Have a pattern across the table associated with them

Effective Nuclear Charge (Zeff)

+Z INNER SHELL OR CORE ELECTRONS OUTER SHELL OR VALENCE ELECTRONS OUTERMOST s ELECTRONS PARTIALLY FILLED SUBLEVELS FOR MAIN GROUP.....THE ns AND np ELECTRONSFOR MAIN GROUP..... THE GROUP NUMBER PERIODICITY OF CHEMICAL PROPERTIES RESULT FROM PERIODICITY OF VALENCE ELECTRONS FILLED ORBITALS

Be +4 VALENCE ELECTRONS DO NOT EXPERIENCE FULL POSITIVE CHARGE ARE SHEILDED Z eff = Z -  EnEn INCREASE INCINC ORBITAL E LOWER IN ATOMS WITH HIGH Z eff

Periodic Properties 1. Ionization Energy 2. Atomic Radius 3. Electron Affinity 4. Electronegativity

Ionization Energy Energy required to remove an electron from an atom If removing valence electrons: 1 st ionization energy

IONIZATION ENERGY E REQUIRED TO REMOVE THE OUTERMOST ELECTRON FROM AN ATOM OR ION IN ITS GASEOUS STATE Z eff INCREASE n IE DECDEC INCREASE IE 1 < IE 2 < IE 3, ETC LOWER IE: MORE EASILY ATOM FORMS CATIONS MORE METALLIC CHARACTER FOR ELEMENT

Atomic Radius Size of the radius of the atom Comparison vs. Ionic radius –Metals: AR is greater than IR (loss of e-) –Non-metals: IR is greater than AR (gain of e-)

ATOMIC RADII DEFINED BY SIZE OF OUTERMOST ORBITALS Z eff INCREASE n r INCINC DECREASE oooooooo o o o o o o oo o o o o o o CATION < ATOM ANION > ATOM

Electron Affinity Tendency of a non-bonded atom to attract electrons to itself Non-metals have higher electron affinities because of their valence electrons

Electonegativity Tendency of elements who are bonded to attract electrons to themselves

ELECTRONEGATIVITY A MEASURE OF THE POWER OF AN ATOM TO ATTRACT ELECTRONS TO ITSELF HIGH , LARGE Z eff, LOW n UNFILLED ORBITAL....NON-METALS Z eff INCREASE n  DECDEC HIGH  : MORE EASILY ATOM FORMS ANIONS MORE NON-METALLIC CHARACTER TO ELEMENT

MAGNETIC PROPERTIES MAGNETIC FIELDS CAUSED BY SPINNING ELECTRONS DIAMAGNETIC: PARAMAGNETIC: NO UNPAIRED ELECTRONS NO ATTRACTION TO APPLIED MAGNETIC FIELD UNPAIRED ELECTRONS ATTRACTED TO APPLIED MAGNETIC FIELD

ARRANGE THE FOLLOWING IN INCREASING ORDER: Si, P, S ATOMIC RADIUS IONIZATION ENERGY ELECTRONEGATIVITY < Na, K, Cl ATOMIC RADIUS IONIZATION ENERGY ELECTRONEGATIVITY < Cs, Fe, S ATOMIC RADIUS IONIZATION ENERGY ELECTRONEGATIVITY < S P Si Si P S Si P S Cl Na K K Na Cl K Na Cl S Fe Cs Cs Fe S

ENERGYENERGY A B C ARRANGE IN ORDER OF: INCREASING IONIZATION ENERGY DECREASING ELECTRONEGATIVITY WHICH IS DIAMAGNETIC AND WHICH IS PARAMAGNETIC? C IS PARAMAGNETIC C < A < B C > A > B