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General Biology: Chemical Context of Life

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Terms in this set (20)

  • What is matter?

    Matter is anything that takes up space and has mass.

  • Define an element.

    An element is a substance that cannot be broken down to other substances by chemical reactions.

  • What is a compound?

    A compound is a substance consisting of two or more elements in a fixed ratio with different characteristics from its elements.

  • What is an atom?

    An atom is the smallest unit of matter that retains the properties of an element.

  • Name the three main subatomic particles and their charges.

    Protons (positive), neutrons (no charge), and electrons (negative).

  • Where are protons and neutrons located in an atom?

    Protons and neutrons form the atomic nucleus at the center of the atom.

  • What determines an element's atomic number?

    The atomic number is the number of protons in the nucleus of an atom.

  • How is atomic mass approximated?

    Atomic mass is approximated by the mass number, the sum of protons and neutrons in the nucleus.

  • What are isotopes?

    Isotopes are atoms of the same element with different numbers of neutrons.

  • What is electronegativity?

    Electronegativity is an atom's attraction for electrons in a covalent bond.

  • Describe a covalent bond.

    A covalent bond is the sharing of a pair of valence electrons between two atoms.

  • What is the difference between polar and nonpolar covalent bonds?

    In nonpolar covalent bonds, electrons are shared equally; in polar covalent bonds, electrons are shared unequally due to differing electronegativities.

  • What is an ionic bond?

    An ionic bond is an attraction between oppositely charged ions formed by electron transfer.

  • Define cation and anion.

    A cation is a positively charged ion; an anion is a negatively charged ion.

  • What are salts in chemistry?

    Salts are ionic compounds formed by ionic bonds, often found as crystals like sodium chloride.

  • What is a hydrogen bond?

    A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom.

  • What determines the chemical behavior of an atom?

    The distribution of valence electrons in the outermost shell determines an atom's chemical behavior.

  • Why are elements with full valence shells chemically inert?

    Elements with full valence shells are chemically inert because they do not tend to share or transfer electrons.

  • What is a molecule?

    A molecule consists of two or more atoms held together by covalent bonds.

  • How is a structural formula different from a molecular formula?

    A structural formula shows the arrangement of atoms and bonds; a molecular formula shows only the number of atoms of each element.