The Periodic Table J. W. Dobereiner -German chemist -classified elements into groups=triads -all...

The Periodic TableJ. W. Dobereiner-German chemist-classified elements into groups=triads

-all undergo similar chemical rxn’s/chemical properties-as the atomic mass# increases for elements in a triad, so do physical properties: density, melting pt, boiling pt, etc (PT trends!!)-atomic mass of middle element is between other 2 elements

ex/Cl, Br, I Cl = 35.453 Cl I

Br = 79.904 35.453 + 126.904 = 81.179I = 126.904 2

Dimitri Mendeleev-Russian chemist-recognized repeating patterns in chemical & physical properties if elements are arranged in order of atomic mass-Periodic Law= Periodicity-1st Periodic Table-1869-elements of similar properties arranged in rows, not columns like today’s periodic table

Alkali Metals-IA (1)

-Demo: Triad Li,Na,KLi + O2 Li2O gray covering/medium react group

Li + H2O LiOH + H2 high

Li + HCl LiCl + H2 extremely high

-flame test-soft, cut with a spatula-shiny inside, dull oxidation covering outside-light, low density < H2O-1 valence e-

-give up 1e-

-+1 charge charged=stable-Fr-most highly reactive metal/radioactive t1/2<1min-Cs-radioactive-medical machines/radioactive t1/2<4yrs

cancer treatments radioactive-K-mineral animals/macronutrients plants-Na-mineral animals-neuron firing & muscle contraction-Li-treatment manic depressiveness

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Alkaline Earth Metals-IIA (2)-Demo: Triad Mg,Ca,Sr

Mg + O2 MgO gray/white/slow react group

Mg + H2O Mg(OH)2 + H2 white precipitate/medium

Mg + HCl MgCl2 + H2 high

-flame test-harder than group 1-shiny under corrosion-light but denser than group 1-2 valence e-

-+2 charge positive=metal-Mg-old camera flashes, camping-start fire metal block and striker-Ca-bones Ca3(PO4)2 , CaCO3=strong protein=flexible osteoporosis neuron firing fireworks orange-Sr-fireworks red

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http://www.youtube.com/watch?v=VUgF

zCjsRzE

-Ra-Madam Marie Curie-died leukemia from radiation exposure radioactive element cancer treatment surface forms-medicine-Ba-upper and lower GI tests-medicine since shows up on Xray unlike internal organs

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Transition Metals-B’s (3-12)-Demo: Sn,Ga,Pb,Pt,Hg,Cu,Fe

Fe + O2 Fe2O3 slow/some slower & some faster

Fe + HCl FeCl3 + H2 medium/some slower & some

faster

Zn + HNO3 Zn(NO3)2 + Nox + H2 also Cu

-most solids-many colors-various physical & chemical properties-alloys ex/brass Cu + Zn

steel Fe + C 99%Fe+1%C=brittle steel=titanic 99.5%Fe+.5%C=strong/flexible steel

-W-filaments incadescent bulbs since mpt high grade-Au,Ag,Pt-jewelry, electronics-excellent conductors-Cu-household wiring, electronics not as good as Au,Ag-Al-not good electrical conductivity <1960’s overheat .:house fires-Pb-lead/heavy metal poisoning-old paints, gas additive octane-Hg-thermometer-heavy metal poisoning

Smog + H2O HNO3

acid rain

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-Metalloids-metal+nonmetal properties border staircase electronics-Si,Ge,As transistors, diodes, microchips

photocells

Nonmetals-IIIA-VIIA (13-17)

-Halogens-group 17 kill bacteria, sterilize, toxic to cells F-toothpaste, water supplies, mouthwashes

Cl-pools, water supplies, bleach Br-pools, water supplies I-methalate, prep for surgery(brown fluid) disinfecting

-N-78% air food protein synthesis nitrogen fixation-bacteria, plants, animals cycle macronutrient plants N,P,K

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-P-macronutrient plants-soil-phosphates-DNA,RNA,ATP,ADP,AMP,creatine phosphate=energy carier

molecules

-O-21% air H2O food O2

required for process respiration carbCO2+H2O+energy required for process photosynth H2O+CO2+energycarb+O2

Noble Gases-VIIIA (18)-gases room temperature-8 valence e-, full outer level-happy, stable, inert, normally not react Xe+UUXe6 rare, done in lab-neon signs Ne-red/orange Ar-pink Xe-white/camera flash/high powered movie projectors-Rn-radioactive gas synthetically made or natural naturally-ores in mountains ex/Pa mandatory testing done on purchase house Pa cancer causing childbirth defects arthritis

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Periodic Table Trends1)Atomic Radius-size of a neutral atom effected by: #electrons-group #valence electrons-period move across a period, greater nucleus +charge, greater pull electrons towards nucleus

ex/Se or O Se

Ionic Radii

2)Ionic Radius-size of a charged atom effected by: #electrons #valence electrons

+atom, less valence electrons, greater pull by the nuclear protons.

-atom, more valence electrons, less pull by nuclear protons.

ex/Ca+2 or H+1 Ca+2

3)Reactivity-ability to accept or donate electronseffected by: #valence electronsElectronegativity-Element wants an electron.

nonmetals-high electronegIonization-Energy needed to strip away electron outer

energy level.Electronegativity~Ionization

ex/ Fe or Y Y N or Cl Cl

Best Nonmetal

Best Metal

Fr

F

1. Largest atom?2. Smallest atom?3. Elements in PT greatest radii?4. Elements in PT lowest radii?

1. Most electronegative atom?2. Least electronegative atom?3. Elements in PT greatest electronegativity?4. Elements in PT lowest electronegativity?

1. Most ionization energy atom?2. Least ionization energy atom?3. Elements in PT greatest ionization energy?4. Elements in PT lowest ionization energy?