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Mastering biology chapter 2 Flashcards

Mastering biology chapter 2
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  • What is an element?
    A substance that cannot be broken down into other substances by chemical reactions.
  • What is the smallest unit of matter that retains the properties of an element?
    An atom.
  • What are the four most common elements in living organisms?
    Carbon, hydrogen, oxygen, and nitrogen.
  • What is a compound?
    A substance consisting of two or more elements in a fixed ratio.
  • What is the significance of trace elements?
    They are required by an organism in only minute quantities but are essential for life.
  • What is an isotope?
    Atoms of the same element with different numbers of neutrons.
  • What is a covalent bond?
    A chemical bond formed by the sharing of electron pairs between atoms.
  • What is an ionic bond?
    A chemical bond resulting from the attraction between oppositely charged ions.
  • What is electronegativity?
    The ability of an atom to attract electrons in a covalent bond.
  • What is a hydrogen bond?
    A weak bond between two molecules resulting from an electrostatic attraction.
  • What is the role of valence electrons in chemical bonding?
    They determine how atoms interact and bond with each other.
  • What is a polar covalent bond?
    A covalent bond in which electrons are shared unequally.
  • What is a molecule?
    Two or more atoms held together by covalent bonds.
  • What is the difference between a molecule and a compound?
    A molecule is two or more atoms bonded together; a compound is a molecule with different elements.
  • What is the atomic number of an element?
    The number of protons in the nucleus of an atom.
  • What is the mass number of an atom?
    The sum of protons and neutrons in the nucleus.
  • What is a chemical reaction?
    The process of making and breaking chemical bonds, leading to changes in the composition of matter.
  • What is a reactant in a chemical reaction?
    A starting material in a chemical reaction.
  • What is a product in a chemical reaction?
    A substance formed as a result of a chemical reaction.
  • What is the law of conservation of mass?
    Matter is not created or destroyed in a chemical reaction.