The Periodic Table

Dobereiner Organized elements into groups of three with similar properties called triads

Newlands Organized elements into 7 rows of 7 elements each (49 known elements) Noticed a repetition of properties after every 7 th element Call this pattern: Law of Octaves

Mendeleev Russian scientist Arranged elements in order of increasing atomic mass (Periodic Law) Left blank spaces for unknown elements Accurately predicted the properties for unknown elements (example: Germanium) Properties can be repetitive over a row larger than 7

Moseley Noticed that certain elements were not in families with the same properties when they were arranged according to atomic mass Arranged elements according to atomic number (Modern Periodic Law)

Seaborg Pulled the “f” electrons out from the main body of the table and established the Lanthanide and Actinide series

Families of the Periodic Table Column Number Family Name Number of Valence e - s 1 Alkali Metals 1 2 Alkaline Earth Metals 2 3 Boron Family 3 4 Carbon Family 4 5 Nitrogen Family 5 6Chalcogens6 7Halogens7 8 Noble Gases 8

Metals Loose electrons (oxidation) to form ions that are positively charged (cations) Good conductors (allow energy to flow through them) of heat and electricity Have 3 or less valence electrons

Non-metals Gain electrons (reduction) in order to form negatively charged ions (anions) Good insulators (don’t allow heat or electricity to flow through them) 4 or more valence electrons

Metalloids Found on the periodic table along the “staircase” Have properties of both metals and non- metals depending upon the particular situation Also called the semi-metals

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

+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