the periodic table

THE PERIODIC TABLE

HistoryMid 1800s 70 known elementsDmitri Mendeleev - 1st to arrange elements systematically & logicallyColumn by increasing atomic massArranged columns by similar propertiesLeft blanks (no known element with right mass and properties)

Mendeleevs Periodic Table

Ti = 50Zr = 90? = 180V = 51Nb = 94Ta = 182Cr = 52Mo = 96W = 186Mn = 55Rh = 104.4Pt = 197.4Fe = 56Ru = 104.4Ir = 198Ni = Co = 59Pl = 106.6Os = 199H = 1Cu = 63.4Ag = 108Hg = 200Be = 9.4Mg = 24Zn = 65.4Cd = 112B = 11Al = 27.4? = 68Ur = 116Au = 197?C = 12Si = 28? = 70Sn = 118N = 14P = 31As = 75Sb = 122Bi = 210O = 16S = 32Se = 79.4Te = 128?F = 19Cl = 35.5Br = 80I = 127Li = 7Na = 23K = 39Rb = 85.4Cs = 133Tl = 204Ca = 40Sr =87.6Ba = 137Pb = 207? = 45Ce = 92?Er = 56La = 94?Yt = 60Di = 95?In = 75.6Th = 118?

History contd.1913 Henry Moseley (British physicist) determined the atomic numbers of the elements

Periodic Table was rearranged according to atomic numbers.

Current arrangement

1A8A011H2A3A4A5A6A7A2He23Li4Be5B6C7N8O9F10Ne311Na12Mg3B4B5B6B7B8B8B8B1B2B13Al14Si15P16S17Cl18Ar419K20Ca21Sc22Ti23V24Cr25Mn26Fe27Co28Ni29Cu30Zn31Ga32Ge33As34Se35Br36Kr537Rb38Sr39Y40Zr41Nb42Mo43Tc44Ru45Rh46Pd47Ag48Cd49In50Sn51Sb52Te53I54Xe655Cs56Ba57La72Hf73Ta74W75Re76Os77Ir78Pt79Au80Hg81Tl82Pb83Bi84Po85At86Rn787Fr88Ra89Ac104Rf105Db106Sg107Bh108Hs109Mt110111112114116118

Lanthanide Series 58Ce59Pr60Nd61Pm62Sm63Eu64Gd65Tb66Dy67Ho68Er69Tm70Yb71Lu Actinide Series90Th91Pa92U93Np94Pu95Am96Cm97Bk98Cf99Es100Fm101Md102No103Lr

The Periodic LawElements have a periodic repetition of their physical and chemical properties when arranged by increasing atomic number.

Types of ElementsMetals

Metals (characteristics due to the sea of free moving electrons)Lustrous (shiny) appearanceMalleable & ductileConduct heat & electricityTend lose e- to form cationsLocated on left side of tableGenerally solids at room temperatureMercury liquidReact with acids (some)


Nonmetals

NonmetalsDull appearanceBrittlePoor conductors of heat & electricityTend to gain e- to form anionsLocated on right side of tableHydrogen on the leftMany are gases at room temperatureDo not react with acids


Nonmetals

Metalloids

MetalloidsLie between metals and nonmetals on the table (stair-step)Have properties of both metals and non metalsMainly solids at room temperature

Symbol ColorsNatural state at room temperatureBlack solidsRed gasesBlue (green) liquidsWhite man made elements

Table OrganizationRows periods (1-7)

11H2He23Li4Be5B6C7N8O9F10Ne311Na12Mg13Al14Si15P16S17Cl18Ar419K20Ca21Sc22Ti23V24Cr25Mn26Fe27Co28Ni29Cu30Zn31Ga32Ge33As34Se35Br36Kr537Rb38Sr39Y40Zr41Nb42Mo43Tc44Ru45Rh46Pd47Ag48Cd49In50Sn51Sb52Te53I54Xe655Cs56Ba57La72Hf73Ta74W75Re76Os77Ir78Pt79Au80Hg81Tl82Pb83Bi84Po85At86Rn787Fr88Ra89Ac104Rf105Db106Sg107Bh108Hs109Mt110111112114116118


Table OrganizationRows periods (1-7)Columns groups or familiesGroups1A 8A Representative elementss-block & p-block1B 8B

Group Names1A Alkali Metals

Group Names1A Alkali Metals2A Alkaline Earth Metals

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family5A Nitrogen Family

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family5A Nitrogen Family6A Oxygen Family

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family5A Nitrogen Family6A Oxygen Family7A Halogens

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family5A Nitrogen Family6A Oxygen Family7A Halogens8A or 0 Noble Gases

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family5A Nitrogen Family6A Oxygen Family7A Halogens8A or 0 Noble Gasesd-block Transition Metals

Group Names1A Alkali Metals2A Alkaline Earth Metals3A Boron Family4A Carbon Family5A Nitrogen Family6A Oxygen Family7A Halogens8A or 0 Noble Gasesd-block Transition Metalsf-block Inner Transition MetalsLanthanide seriesActinide series

Miscellaneous FactsAtomic #s 83 are radioactiveSeven diatomic elementsH2N2O2F2Cl2Br2I2What are the representative elements?The first 20 elements on the periodic tableThey form a 7 on the periodic tableH2 N2 O2 F2Cl2Br2I2

Periodic Trends

Periodic TrendsMany properties of the elements change in a predictable way as you move through the periodic tableThese systematic variations are called periodic trends

Atomic RadiusDistance from center of an atoms nucleus to its outermost electrons

Atomic Radius TrendDown a groupIncreases as you go down a groupWhy?Adding another principal energy level where the outermost electrons resideShielding increases which decreases the effective nuclear charge on the outer electronsAtoms are getting bigger

Atomic Radius Trend, contd.Across a period (row)Decreases across a rowWhy?Gain protons as move from left to right (gaining positive charge or increasing effective nuclear charge)Increases the pull on the electrons that are all about the same distance from the nucleusSame principal energy levelShielding is constant for all electronsA stronger attractive force shrinks the electrons orbitals and makes the atom smaller

Atomic Radius Trend, contd.

In Your Notes.Write a definition of atomic radius in your own wordsWhat is the group trend?Explain whyWhat is the period trend?Explain why.Share your definition, trends and explanations with a partner

IonsAtoms that are charged (not neutral)Created by atoms gaining or losing e-Loss of e- - positive ion called a cationGain of e- - negative ion called an anionNo change in # of p+

Ionic Size (Radius)Metals: neutral atom is larger than its cationCations are formed when atoms lose their valence electron(s) In turn, they lose an entire principal energy levelThis reduces the repulsive force between the remaining electrons allowing them to be pulled closer to the nucleus Increases the effective nuclear charge (remaining electrons feel a stronger attraction to the nucleus; i.e., fewer e-, same number of p+).Li atomLi+ ion1s22s11s2Distance from the center of the nucleus to the outermost electron

Ionic Size, contd.Nonmetals: neutral atom is smaller than its anionAnions are formed when atoms gain electron(s) to complete their outermost energy levelThis increases the electric repulsive forces between the electrons spreading them further apartDecreases the effective nuclear charge (shielding stays the same)F atomF-1 ion1s22s22p51s22s22p6

Ionic Size, contd.Group Trend: generally increase going downPeriod Trend: generally decreases across the row

Ionic Size, contd.

Ionization EnergyEnergy required to remove a valence electron Approximates how strongly an atom holds onto its outermost electronsHigh ionization energy = tightly held electrons (hard to remove)Low ionization energy = outermost electrons easily removed giving the atom a positive charge

Ionization Energy TrendsGroup Trend: decreases down a groupValence electrons feel less of the positive charge from nucleus because:As the size of the atom increases, the shielding from the filled energy levels increases and the distance from the nucleus increasesThe valence electrons feel less of the positive charge from the nucleus (decreasing effective nuclear charge)

Ionization Energy Trends, contdPeriod Trend: increases across a periodNuclear charge increases and the shielding effect is constant (same distance from nucleus)Greater attraction from the nucleusA stronger attractive force shrinks the electrons orbitals and makes the atom smallerNoble gases have the highest ionization energies in any period

Ionization Energy, contdFirst Ionization Energy energy required to remove the outermost electronSecond Ionization Energy energy required to remove the next electronSuccessive Ionization Energy energy required to remove additional electrons (3rd, 4th, etc.)

Ionization Energy Trends, contd

ElectronegativityAbility of an atom to attract electrons in a chemical bondFluorine is the most electronegative elementNoble gases have no electronegativityCannot be directly measured

Electronegativity TrendsGroup Trend: increases going UP a groupLess shielding, stronger effective nuclear chargePeriod Trend: Increases across a periodConstant shielding, increasing effective nuclear charge

Electronegativity Trends, contd.

ReactivityMetalBased on ionization energyThe lower the ionization energy the higher the chemical reactivity Increased metallic character (larger sea of electrons)Which metal is most reactive?NonmetalsUses electronegativityThe higher the electronegativity the higher the chemical reactivityWhich nonmetal is most reactive?

PracticeWhich of the following atoms has the highest electronegativity?Cs, K, or LiSi, Al, or SWhich of following metals is more reactive?Ca, Sr, or BaWhich of the metals in question 2 has the lowest ionization energy?

PracticeWhich of the following metals has the highest ionization energy?Ni, Mn, or Zn

Octet RuleAtoms tend to lose, gain or share electrons in order to get a full set of eight valence electronsExceptions:Duet rule: Hydrogen gains 1 get to look like HeLithium and beryllium lose 1 and 2, respectively, to look like HeFilled s & p orbitals are extremely stable

IsoelectricAtoms &/or ions that have the same number of electronsAlso same electron configurationExample:Na+, Ne, & F- All have 10 electronsAll have the same electron configuration

Practice:Which of the following atoms &/or ions are isoelectric?K+, P3-, F-, Ca2+, Na+, Sr2+How many electrons do these have?Which one has the smallest radius?

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the periodic table

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