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Periodic Properties of the Elements - General Chemistry

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Terms in this set (29)

  • Who independently developed the early periodic table based on element properties?
    Dmitri Mendeleev and Lothar Meyer independently concluded how elements should be grouped.
  • What fundamental property did Mendeleev use to organize the periodic table?
    Mendeleev used atomic masses and chemical properties to organize the table.
  • What is the modern basis for the periodic property of elements?
    The atomic number, or number of protons, is the basis for periodic properties.
  • Define periodicity in the context of the periodic table.
    Periodicity is the repetitive pattern of element properties based on atomic number.
  • What is effective nuclear charge (\(Z_{eff}\))?
    It is the net positive charge experienced by valence electrons: Z_{eff} = Z - S, where Z is atomic number and S is screening by inner electrons.
  • How does effective nuclear charge change across a period and down a group?
    Increases across a period and increases slightly down a group.
  • What is the bonding atomic radius?
    Half the distance between nuclei of two bonded atoms.
  • How does atomic radius change across a period and down a group?
    Atomic radius decreases across a period and increases down a group.
  • Why are cations smaller than their parent atoms?
    Cations lose outer electrons, reducing electron-electron repulsions and size.
  • Why are anions larger than their parent atoms?
    Anions gain electrons, increasing electron-electron repulsions and size.
  • What trend is observed in ionic size within an isoelectronic series?
    Ionic size decreases with increasing nuclear charge for ions with the same number of electrons.
  • Define ionization energy.
    Minimum energy required to remove an electron from a gaseous atom or ion.
  • How does first ionization energy generally change across a period and down a group?
    First ionization energy increases across a period and decreases down a group.
  • What causes irregularities in ionization energy trends?
    Irregularities occur when electrons enter a new sublevel or pair in an orbital, affecting electron repulsions.
  • From which electrons are cations formed?
    Electrons are lost from the highest energy level (largest n value).
  • What is electron affinity?
    Energy change when an electron is added to a gaseous atom; usually exothermic (negative).
  • How does electron affinity trend across a period and down a group?
    Electron affinity generally increases across a period and changes little down a group.
  • What are the general properties of metals?
    Metals have shiny luster, conduct heat and electricity, are malleable and ductile, and form cations easily.
  • How do metal oxides generally behave chemically?
    Metal oxides tend to be basic and react with acids.
  • What are the general properties of nonmetals?
    Nonmetals can be solid, liquid, or gas; solids are dull and brittle; they have large negative electron affinities and form anions.
  • How do nonmetal oxides generally behave chemically?
    Nonmetal oxides are mostly acidic.
  • What characterizes metalloids?
    Metalloids have properties intermediate between metals and nonmetals and can be semiconductors.
  • What are the key properties of alkali metals?
    Soft, metallic solids with low densities, low melting points, and low ionization energies; react exothermically with water.
  • How do alkali metals differ in their reaction with oxygen?
    Li forms oxides, Na forms peroxides, and K, Rb, Cs form superoxides.
  • What are the key properties of alkaline earth metals?
    Higher densities and melting points than alkali metals; form +2 cations; reactivity increases down the group.
  • What is unique about oxygen allotropes?
    Oxygen exists as dioxygen (O2) and ozone (O3).
  • What are the general properties of halogens?
    Typical nonmetals with highly negative electron affinities; exist as anions and form metal halides.
  • What are the general properties of noble gases?
    Monatomic gases with very high ionization energies and positive electron affinities; mostly unreactive.
  • How does hydrogen behave chemically?
    Hydrogen forms covalent acids like HCl and hydride anions (H−) when reacting with metals.