Periodic Table

ELEMENTS All atoms of a specific element are alike All atoms of different elements are different 90 naturally occurring Arranged on Periodic Table to show trends

Mendeleev (1869) Organized table by... Atomic mass Thought pattern must exist between all elements Elements in columns show similar properties… Both physical and chemical! Predicted properties of “missing” elements

Mendeleev’s Table

Moseley (c. 1914) rearranged table by... Atomic number determined atomic number of elements by determining number of protons in element

Moseley’s Table

Seaborg (1944) rearranged Periodic Table with... Lanthanide and Actinide Series pulled out/separated from main Periodic Table discovered countless isotopes & 10 new elements

Before Seaborg

3-D Alexander’s Arrangement of Elements

Information from Periodic Table Atomic number Atomic mass Chemical symbol Chemical name

Periodic Law The physical and chemical properties of the elements are periodic functions of their atomic number

Columns of Table = “groups” or “families” Newer designation: main families labeled with Roman Numeral and letter ‘A’ Elements within the same family have similar but not identical properties Electron configuration varies periodically

Rows of Table = “periods” Properties are not alike within a period 7 periods Number of energy levels in atom 2 additional rows at bottom of table are Lanthanide and Actinide series and belong to periods 6 and 7 Seaborg's Extended Periodic Table

Names of Families Group 1 or IA Group 2 or IIA Group13 or IIIA Group 14 or IVA Group 15 or VA Group 16 or VIA Group 17 or VIIA Group 18 or VIIIA Groups 3-12 Lanthanide & Actinide series Alkali metals Alkaline Earth metals Boron family Carbon family Nitrogen family Oxygen family Halogens Noble gases Transition metals Rare Earth metals

Metals Found to LEFT of zigzag line on table Good conductors of heat & electricity Malleable Ductile High melting points Luster Tend to lose electrons

Nonmetals Found to RIGHT of zigzag line on table Poor conductors of heat & electricity Brittle when solid Dull Low melting points Tend to gain electrons

Metalloids Found along both sides of zigzag line Properties of both metals & nonmetals Okay conductors of heat & electricity Shiny or dull

Trends Valence number Charge of ion Tendency to gain or lose electrons Reactivity Atomic size (radius) Metallic vs. nonmetallic properties Ionization energy Electron affinity Electronegativity

Atomic Radius PERIOD 2 PERIOD 3

Ionization Energy PERIOD 2 PERIOD 3

Electronegativity PERIOD 2 PERIOD 3

Across a Period radius decreases ionization energy increases electronegativity increases b/c number of valence electrons increases… so EMF increases… so valence electrons held more tightly…

Atomic Radius Family IA Family IIA

Ionization Energy Family IA Family IIA

Electronegativity Family IA Family IIA

Down a Family radius increases ionization energy decreases electronegativity decreases b/c number of energy levels increases… so valence electrons held less tightly…

Electron Organization Found in electron clouds - also described as energy levels Limited space in each cloud Electrons want to be close to the nucleus because of EMF Start with by filling the lowest energy level and working their way out. Want to be in pairs.

Energy Levels Energy LevelMaximum Number of Electrons Level One2 Level Two8 Level Three18 Level Four32 Level Five50 Level Six72

Valence Electrons for the 8 major families Valence Electron = An electron located on the outer most shell Roman Numeral tells number of valence electrons for all chemicals in the family. Each element wants to achieve 8 valence electrons to be stable Drawn as dot diagrams.

Electron Dot Diagram X Always start HERE X = Chemical Symbol = A valence electron

Octet Rule The tendency of atoms to gain or lose electrons so they acquire eight electrons in their outer energy level

Who am I? Use the clues and a periodic table to predict the element. The number of clues is shown in the lower right corner.

1. Who am I? Very good ability to conduct electricity When combined with other elements, usually give up 1 valence electron Only one letter in symbol Potassium! (K) 3 clues

2. Who am I? More valence electrons than oxygen More protons than calcium Fewer protons than krypton Bromine ! (Br) 3 clues

3. Who am I? Poor conductor Usually found as a gas Do not bond well with others (like to be alone) Sometimes found in signs outside restaurants Neon ! (Ne) 4 clues

4. Who am I? Second largest atomic radius of period One of most reactive in the family One more proton than Rubidium Strontium ! (Sr) 3 clues

5. Who am I? Usually found as a gas Very reactive Lightest element in family Often form -1 ion Fluorine! (F) 4 clues

6. Who am I? Radioactive Highest atomic radius in family Usually form -2 ion Polonium ! (Po) 3 clues

7. Who am I? Most commonly form +2 ion Second highest number of protons in family Second largest atomic radius in family Barium! (Ba) 3 clues

8. Who am I? All other members of family are metals Most abundant element in universe Hydrogen ! (H) 2 clues

9. Who am I? Metals, nonmetals, and semi-metals all found in family Same number of protons as the sum of the protons in the two elements directly above 2nd greatest atomic radius in my family Lead ! (Pb) 3 clues

10. Who am I? Smallest atomic radius in my family Family contains metals, nonmetals, and semi-metals Can form positive or negative ion (call this the “skip” family) Carbon ! (C) 3 clues

1. Who am I? Very good ability to conduct electricity When combined with other elements, usually give up 1 valence electron 2nd largest atomic radius in group Cesium! (Cs) 3 clues

2. Who am I? More valence electrons than iodine Fewer protons than rubidium Can hurt Superman Krypton (Kr) 3 clues

3. Who am I? Poor conductor Usually found as a gas Do not bond well with others Can make your voice sound funny Helium ! (He) 4 clues

4. Who am I? 2 nd lowest atomic radius in the group Has twice as many protons as the element above it Can smell like rotten eggs Sulfur ! (S) 3 clues

5. Who am I? Has more valence electrons than lithium Is a metal that sits on the ‘zig- zag’ line Is not radioactive Aluminum! (Al) 3 clues

6. Who am I? Has 5 occupied energy levels It is shiny and malleable Has a symbol that isn’t derived from the it’s English name Has a atomic number less than 75 I am NOT very valuable. Tin ! (Sn) 5 clues

7. Who am I? Largest atomic radius on the periodic table Francium (Fr) 1 clues