UNIT 5 – Periodic Laws THE PERIODIC CHART

HISTORY Dalton:grouped elements by their properties Berzelius:gave elements names and symbols ( important because he established order) Newlands law of the octaves 1 st and 8 th counted on his chart were similar Doberiener developed groups of 3’s called triads, had math rule mass of 1 st plus mass of 3 rd divided by 2 = mass of 2 nd Meyer: graphed elements by masses

Mendeleyev: University professor in Russia, he published the Periodic Chart of elements on March 9, 1869 similar to ours. He developed the groups and series with only 7 major “families”. Ramsey:In the 1890’s the 8 th family was discovered Moseley: grouped chart by the order of atomic # instead of mass. Joliet: produced the 1 st synthetic element in 1936, Tc IUPAC: A committee that take care of our present chart ( meet every other year in Paris )

Parts Families (8) named columns Groups (18) numbered columns Series / Periods (8) numbered rows

FAMILY NAMES ALKALI- NITROGEN ALKALINE- CHALCOGEN “NO NAME”(transition)- HALOGEN CARBON- INERT (NOBLE)

Regions of the Chart Active Metals “s” first and second groups of elements Transition “d” groups 3 – 12 metals “p” elements of groups 13 – 18 metals / metalloids / nonmetals Rare Earth “f” Rare natural metals and synthetic elements

The Steps Metals To the left of the steps (zig-zag) Metalloids On / near the steps Nonmetals To the right of the steps

Periodic Properties 1. Atom Size a) down - family or group increases, add new layers of electrons ( shells/energy levels) b) to right - is smaller, protons have stronger pull Fr is the largest F is the smallest 2. Ion Size a) Metals who lose electrons are called cations M+ M+ is smaller than M atom b) Nonmetals gain electrons are called anions Nm- Nm- is larger than Nm atoms 8 th family normally does not form ions

3. Activity a)Groups/families of metals are down more active b) Groups/Families of Nm up is more active c) Across ( period/series ) more active less more active

4 Metallic Properties increase as going down increase at left

5 Ionization Energy (IE) The Energy needed to remove one electron from an element 1st IE2 nd IE3 rd IE4 th IE Least EnergyMore ESomewhat more Most E easy: this depends on the # of valence electrons Metals have a LOW IE hard: on inner shells, once valence are gone Nonmetals have HIGH IE 6 Electron Affinity (EA) the attraction of an element for its outer shell electron Metals have a LOW EA / Nonmetals have HIGH EA 7 Electronegativity (EN) the energy exchange as a an atom gains one electron Metals have a LOW EN/ Nonmetals have HIGH EN Glitch : where a family or group doesn’t fit a pattern, the most common glitch is 13 group, but groups 2-3, 8, 10 and 15 sometimes break the rules