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Indietro

chapter 3

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Termini in questo insieme (20)

  • What is a periodic property?
    A periodic property is a physical or chemical property of an element that is predictable based on its position in the periodic table.
  • What does the Periodic Law state?
    The Periodic Law states that when elements are arranged in order of increasing atomic mass, certain sets of properties recur periodically.
  • How are elements arranged in the modern periodic table?
    Elements are arranged in order of increasing atomic number, with rows called periods and columns called groups or families.
  • What are the main classifications of elements in the periodic table?
    Elements are classified as metals, nonmetals, and metalloids. They are also divided into main-group elements (A) and transition elements (B).
  • What is an electron configuration?
    An electron configuration describes the arrangement of electrons in an atom's orbitals.
  • What is the Pauli Exclusion Principle?
    No two electrons in an atom can have the same set of four quantum numbers; thus, an orbital can hold a maximum of two electrons with opposite spins.
  • What is electron spin and its significance?
    Electron spin is a fundamental property with two possible orientations (up or down). Paired electrons in an orbital must have opposite spins.
  • What causes sublevel energy splitting in multi-electron atoms?
    Sublevel splitting is caused by electron-electron interactions, shielding, and penetration effects, making sublevels in the same principal energy level have different energies.
  • What is shielding in atoms?
    Shielding occurs when inner electrons reduce the effective nuclear charge felt by outer electrons by repelling them.
  • What is penetration in atomic orbitals?
    Penetration refers to how an electron in a sublevel can get closer to the nucleus, experiencing less shielding and a stronger attraction.
  • What is the aufbau principle?
    Electrons fill atomic orbitals starting from the lowest energy level to higher energy levels.
  • What is Hund's Rule?
    When filling degenerate orbitals, electrons occupy them singly with parallel spins before pairing up.
  • How do you determine valence electrons from electron configuration?
    Valence electrons are the electrons in the outermost principal energy level (highest n value) of an atom.
  • How do main-group elements' group numbers relate to valence electrons?
    The group number of a main-group element equals the number of valence electrons it has.
  • What is the general trend of atomic radius in the periodic table?
    Atomic radius increases down a group and decreases across a period from left to right.
  • What is effective nuclear charge (Z_eff)?
    Effective nuclear charge is the net positive charge experienced by an electron after accounting for shielding by other electrons.
  • How does ionization energy change across the periodic table?
    Ionization energy generally increases across a period and decreases down a group.
  • What is electron affinity?
    Electron affinity is the energy change when an electron is added to a neutral atom in the gas phase, often releasing energy (exothermic).
  • What is metallic character and its periodic trend?
    Metallic character describes how closely an element's properties match those of metals; it decreases across a period and increases down a group.
  • How do cation and anion sizes compare to their neutral atoms?
    Cations are smaller than their neutral atoms due to loss of electrons and increased effective nuclear charge; anions are larger due to added electrons and increased electron-electron repulsion.