DMITRI MENDELEEV

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DMITRI MENDELEEV

• ORGANIZED KNOWN ELEMENTS INTO A TABLE
• POSITIONED ELEMENTS SO ELEMENTS WITH SIMILAR
  PROPERTIES IN COLUMNS
• RECOGNIZED THAT PROPERTIES REPEATED PERIODICALLY
  IN A PATTERN

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MENDELEEVS PT
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MENDELEEVS PREDICTIONS

• PREDICTED PROPERTIES OF YET UNDISCOVERED ELEMENTS
• PREDICTIONS BASED ON TRENDS IN COLUMNS AND ROWS
• PREDICTIONS WERE VERY ACCURATE

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PREDICTED PROPERTIES
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MODERN PREDICTIONS
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MODERN PERIODIC TABLE

• MODERN PERIODIC TABLE IS ARRANGED BASED ON ATOMIC
  NUMBER

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LONG FORM PT
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TYPES OF ELEMENTS
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GROUP NAMES
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METAL

• LOSES ELECTRONS WHEN REACTING
• TYPICALLY HAS 1-3 VALENCE ELECTRONS
• FOUND LEFT OF THE STAIR STEPS ON THE PERIODIC
  TABLE

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NONMETAL

• GAINS ELECTRONS WHEN REACTING
• TYPICALLY HAS 5-7 VALENCE ELECTRONS
• FOUND RIGHT OF THE STAIR STEPS ON THE PERIODIC
  TABLE

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METALLOID

• CAN GAIN OR LOSE ELECTRONS WHEN REACTING
• A SUBSTANCE HAVING 3-5 VALENCE ELECTRONS
• FOUND ALONG THE STAIR STEPS ON THE PERIODIC TABLE

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NOBLE GASES

• DO NOT GAIN OR LOSE ELECTRONS SO THEY DO NOT
  REACT
• HAVE FULL VALENCE SHELL (2 FOR He AND 8 FOR
  OTHERS)
• FOUND IN RIGHTMOST COLUMN OF PERIODIC TABLE

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FAMILY CHARACTERISTICS

• ALL HAVE THE SAME NUMBER OF VALENCE ELECTRONS
• SIMILAR CHEMICAL PROPERTIES
• TRENDS OF DENSITY, MP, BP
• TREND OF INCREASING OR DECREASING REACTIVITY

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PERIODIC LAW

• PROPERTIES OF ELEMENTS TEND TO REPEAT IN A
  PATTERN WHEN THE ELEMENTS ARE ARRANGED IN ORDER
  OF INCREASING ATOMIC NUMBER

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ATOMIC SIZE PATTERNS

• GET SMALLER GOING FROM LEFT TO RIGHT ACROSS A
  PERIOD
• ADDING PROTONS PULLS ENERGY LEVELS CLOSER
• ELECTRONS ADDED TO VALENCE SHELL
• GET LARGER GOING FROM TOP TO BOTTOM IN A GROUP
• NEED MORE ENERGY LEVELS TO FIT ALL ELECTRONS

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ION SIZES

• CATIONS ARE SMALLER THAN NEUTRAL ATOMS
• LOST VALENCE SHELL, SO FEWER ENERGY LEVELS
• ANIONS ARE LARGER THAN NEUTRAL ATOMS
• ADDED ELECTRONS REPELL TO MAKE VALENCE SHELL
  LARGER

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UNITS FOR ATOM SIZE

• ANGSTROMS (Å) 1 x 10-10 m
• PICOMETERS (pm) 1 x 10-12 m

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ATOMS AND CATIONS
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ATOMS AND ANIONS
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ATOMIC SIZE (in pm)
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IONIZATION ENERGY

• ENERGY INPUT NEEDED TO REMOVE THE OUTERMOST
  VALENCE ELECTRON FROM AN ATOM
• INCREASES FROM LEFT TO RIGHT
• DECREASES FROM TOP TO BOTTOM

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ELECTRON AFFINITY

• ENERGY RELEASED WHEN AN ELECTRON IS ADDED TO AN
  ATOM
• INCREASES FROM LEFT TO RIGHT
• DECREASES FROM TOP TO BOTTOM

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IE AFFINITY TRENDS
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REACTIVITY TRENDS

• METALS BECOME MORE REACTIVE DOWN THE GROUP
• NONMETALS BECOME LESS REACTIVE DOWN THE GROUP

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ALKALI METAL PROPERTIES

• LOW DENSITY
• LOW MELTING POINTS
• GOOD CONDUCTORS OF ELECTRICITY
• SILVER IN COLOR
• SOFT
• 1 CATION

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ALKALI METALS REACTIONS

• REACT EASILY WITH OXYGEN TO FORM OXIDES
• REACT EXOTHERMICALLY WITH WATER TO FORM STRONG
  BASES (METAL HYDROXIDES) AND H2 GAS
• MUST BE STORED IN OIL TO PREVENT REACTION WITH O2
  
• COMBINE WITH HALOGENS TO FORM SALTS

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HYDROGEN

• NOT AN ALKALI METAL
• IN SAME FAMILY DUE TO HAVING 1 VALENCE ELECTRON
• REACTS WITH HALOGENS BY SHARING ELECTRONS
• REACTS WITH ALKALI METALS BY FORMING A -1 ANION
  CALLED HYDRIDE

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ALKALINE EARTH METAL PROPERTIES

• SIMILAR TO ALKALI METALS
• DO NOT NEED TO BE STORED IN OIL TO PREVENT
  REACTION WITH O2 (FORM HARD OUTER LAYER THAT
  PREVENTS FURTHER REACTION)
• HARDER THAN ALKALI METALS
• 2 CATION

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ALUMINUM FAMILY

• METALS AND METALLOIDS
• 3 CATION
• ALUMINUM IS MOST ABUNDANT METAL IN EARTHS CRUST,
  FOUND AS OXIDE COMPOUND

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CARBON FAMILY

• VARIETY OF PROPERTIES
• CARBON IS ONLY NONMETAL
• SILICON AND GERMANIUM ARE METALLOIDS
• TIN AND LEAD ARE MULTI-VALENCE METALS

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ALLOTROPES

• DIFFERENT FORMS OF AN ELEMENT
• CARBON GRAPHITE, DIAMOND, FULLERENES
• OXYGEN O2 AND O3
• PHOSPHORUS RED AND WHITE

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NITROGEN FAMILY

• N AND P ARE NONMETALS
• As AND Sb ARE METALLOIDS
• Bi IS METAL
• NITROGEN IS ESSENTIAL IN LIVING THINGS, PART OF
  DNA
• WHITE PHOSPHORUS BURSTS INTO FLAME IN OXYGEN

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OXYGEN FAMILY

• MOST ARE NONMETALS (Po IS METALLOID)
• -2 ANION
• OXYGEN IS MOST ABUNDANT ELEMENT ON EARTH 2ND
  MOST REACTIVE ELEMENT
• SULFUR KNOWN FOR BAD SMELLING COMPOUNDS HAS
  MANY ALLOTROPES
• Se IS POOR CONDUCTOR IN DARK BUT GOOD IN LIGHT
  (LIGHT SENSITIVE)

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HALOGENS

• NONMETALS
• -1 ANION BUT ALSO SHARE ELECTRONS
• DIATOMIC
• NOT FOUND IN ELEMENTAL FORM SINCE THEY ARE SO
  REACTIVE
• FORM SALTS WITH GROUP IA AND IIA
• TOXIC, USED TO KILL AND DISINFECT
• F IMPORTANT TO PREVENT TOOTH DECAY
• I IMPORTANT TO THYROID HEALTH

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NOBEL GASES

• FULL VALENCE SHELL
• UNREACTIVE (INERT)
• GASES

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TRANSITION METALS

• SOLIDS AT ROOM TEMP, EXCEPT Hg
• MOST ARE DUCTILE (PULLED INTO WIRE)
• MOST ARE MALLEABLE (CAN BE RE-SHAPED)