The most important tool in chemistry Your New ♥ Best Friend ♥ The Periodic Table The most important tool in chemistry

Periodic Table organization? The periodic table will be your most useful tool; it is organized in two specific ways: 1) increasing atomic number, and 2) similar chemical properties. family – vertical column in PT. -> elements in the same family exhibit similar chemical and physical properties 2

Blocks of the Periodic Table

Periodic Table Activity Procedure: 1.Number the columns 1-18 across the top 2.Number the rows down the left-side 3.Fill-in 5-10 elements that you work with 4.Label the following families: alkali metal, alkaline-earth metal, transition metal, halogen, noble gas

Periodic Table Period – rows numbered 1 to 7. Group – columns numbered 1 to 18; also called Families. Group ¯ ¬Period 5

Periodic Table The periodic table can be most easily be separated into three sections: Metals, non-metals, and metalloids non-metals Metalloids He Metals ¯ B C N O Ne F Noble gases Al Si P S Cl Ar Ga Ge As Se Br Kr In Sn Sb Te I Xe Tl Pb Bi Po At Rn

Characteristics of Metals lustrous appearance. mostly solids that are malleable (shapeable). excellent electrical and thermal conductors. tend to form (+) ions in ionic compounds→give up electrons

Charact. of non-Metals dull appearance. wide diversity in physical states with solids being brittle or soft. poor electrical and thermal conductors (great insulators!). tend to form (-) ions in ionic compounds → gain electrons

Metalloids Metalloids: Those elements with properties of metals or non-metals depending on the bond situation (Including B, Si, Ge, As, Sb, Te)

Periodic Table Alkali metals – Group 1 Alkaline Earth metals – Group 2 Halogens – Group 17 Noble Gases – Group 18 10

Periodic Table Transition metals – Groups 3-12 Inner Transition metals

Periodic Table Practice Symbol At.# Family # Family Name Na 11 1 He 2 18 Li 3 1 Be 4 2 B 5 13 H 1 Alkali metal Noble gas Alkali metal Alkaline earth metal Metalloid Family by itself

Diatomic Molecules Di = 2 Famous German scientist discovered: Cl I F Br O H N 2 2 2 2 2 2 2 Molecules always want to be in pairs and NOT alone

Atomic Radii

Periodic Trends Atomic Size The trend down a group is that atomic size increases as number of the valence shell increases

Periodic Trends Atomic Size The trend across a period is that atomic size decreases because the number of protons increases but no additional energy levels are added. The more + nucleus can draw e- closer

Periodic Trends Ion Size Cations are always smaller than the atom - fewer electrons so each one is held just a little bit tighter. Cation Charge Size Fe(145 pm); Fe2+(74 pm); Fe3+ (64 pm)

Periodic Trends Ion Size Anions are always larger than the atom - more electrons than protons in the nucleus so the charge felt per electron goes down. Anion Charge Size

Periodic Trends 1st Ionization Energy The removal of electrons from an atom can occur two ways: transfer to another atom. “artificially” with external energy. M + Energy  M+ + e- Energy = Ionization Energy (IE)

Ionization Energies

Periodic Trends 1st Ionization Energy Trends in IE are the reverse of atomic size trends. smallest atomic radius highest IE largest atomic radius lowest IE

Periodic Trends Electron Affinity Electron affinity is the attraction of an atom (in the gas phase) for additional electrons. A(g) + e-  A-(g) + Energy (exotherm) The electron obtained always goes into the lowest energy subshell in which there is space available!

Electron Affinity

Periodic Trends Electron Affinity smallest anion radius highest EA largest anion radius lowest EA Think of the electron being in a hole and the electron affinity is related to how deep the hole is!

Periodic Trends Electronegativity The ability for an atom to attract electrons from a neighboring atom smallest atomic radius has highest electronegativity- fluorine 4.0 largest atomic radius lowest electronegativity – Francium 0.7

Electronegativities