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Atoms- Smallest Unit of Matter exam Flashcards

Atoms- Smallest Unit of Matter exam
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  • Atom
    The smallest unit of an element that retains the properties of that element.
  • What are the three subatomic particles?
    Protons, neutrons, and electrons.
  • Atomic Number
    The total number of protons in the nucleus of an atom.
  • What is the charge of a proton?
    Positive (+1).
  • Neutron
    A subatomic particle with no electric charge, found in the nucleus of an atom.
  • What is the mass of an electron?
    Practically negligible, rounded to 0 atomic mass units (AMU).
  • Electron
    A subatomic particle with a negative charge, found orbiting the nucleus.
  • What is the octet rule?
    Atoms are more stable and less reactive when their valence shells are full, typically with 8 electrons.
  • CHNOPS
    A mnemonic for the six key elements in living organisms: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, and Sulfur.
  • What determines the identity of an element?
    The atomic number, or the number of protons in the nucleus.
  • Valence Electrons
    Electrons in the outermost energy shell of an atom.
  • What is the charge of a neutron?
    Neutral (0).
  • Atomic Mass Unit (AMU)
    A unit of mass used to express atomic and molecular weights, approximately equal to the mass of one proton or neutron.
  • What is the charge of an electron?
    Negative (-1).
  • Mass Number
    The total number of protons and neutrons in the nucleus of an atom.
  • What is the significance of the atomic mass?
    It is the average total mass of all the atoms of an element.
  • Electron Shells
    Energy levels where electrons orbit the nucleus of an atom.
  • What is the maximum number of electrons in the first energy shell?
    2 electrons.
  • Nucleus
    The central part of an atom, containing protons and neutrons.
  • What is the maximum number of electrons in the second energy shell?
    8 electrons.
  • Chemical Element
    A pure substance made up of only one type of atom.
  • What are trace elements?
    Elements required for life but in very small amounts.
  • Proton
    A subatomic particle with a positive charge, found in the nucleus of an atom.
  • What is the role of valence electrons in chemical bonding?
    Valence electrons are involved in forming chemical bonds.
  • Atomic Mass
    The average mass of all the isotopes of an element.
  • What is matter?
    Anything that takes up space and has mass.
  • Electron Orbitals
    Three-dimensional regions around the nucleus where electrons are likely to be found.
  • What is the significance of the nucleus in an atom?
    It contains most of the atom's mass and is composed of protons and neutrons.
  • Element Symbol
    A one or two-letter abbreviation for a chemical element.