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General Chemistry: The Atom

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Terms in this set (20)

  • What is an atom?
    An atom is the smallest unit of an element that retains the chemical properties of that element.
  • What are the three main subatomic particles in an atom?
    Protons, neutrons, and electrons.
  • Where are protons located in an atom?
    Protons are located in the nucleus at the center of the atom.
  • What is the charge of a proton?
    A proton has a positive charge (+1).
  • Where are neutrons found in an atom?
    Neutrons are found in the nucleus alongside protons.
  • What is the charge of a neutron?
    A neutron has no charge; it is neutral.
  • Where are electrons located in an atom?
    Electrons orbit the nucleus in the electron cloud or shells.
  • What is the charge of an electron?
    An electron has a negative charge (-1).
  • What determines the atomic number of an element?
    The number of protons in the nucleus defines the atomic number.
  • What is an isotope?
    Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
  • How is the mass number of an atom calculated?
    Mass number = number of protons + number of neutrons.
  • What is the role of electrons in chemical reactions?
    Electrons, especially those in the outermost shell, determine an atom's chemical reactivity.
  • What is the nucleus of an atom?
    The nucleus is the dense central core containing protons and neutrons.
  • Why are atoms electrically neutral?
    Because the number of protons equals electrons, their charges balance out.
  • What is an ion?
    An ion is an atom or molecule with a net electric charge due to loss or gain of electrons.
  • What is the approximate size of an atom?
    Atoms are about 0.1 to 0.5 nanometers in diameter.
  • What is the electron cloud?
    The electron cloud is the region around the nucleus where electrons are likely to be found.
  • How do protons and neutrons compare in mass?
    Protons and neutrons have approximately the same mass, which is much greater than that of electrons.
  • What is atomic mass?
    Atomic mass is the weighted average mass of an element's isotopes, measured in atomic mass units (amu).
  • What defines the identity of an element?
    The number of protons in the nucleus uniquely identifies an element.