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General Biology: Atoms, Molecules, and Chemical Bonds

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Termini in questo insieme (20)

  • What determines the chemical reactivity of an atom?
    The electrons in the outermost or valence shell determine an atom's chemical reactivity.
  • What is the maximum number of electrons in the first three electron shells?
    Shell 1 holds up to 2 electrons, Shell 2 holds up to 8 electrons, and Shell 3 holds up to 8 electrons.
  • When is an atom considered stable?
    An atom is stable when its valence shell is full: 2 electrons in shell 1, 8 in shell 2, and 8 in shell 3.
  • What defines an element?
    The atomic number, which is the number of protons in the nucleus, defines an element.
  • What is the relationship between protons and electrons in a neutral atom?
    In a neutral atom, the number of protons equals the number of electrons.
  • What is the 'octet rule' in chemistry?
    Atoms tend to gain, lose, or share electrons to have 8 electrons in their valence shell, achieving stability.
  • How do atoms with incomplete outer shells achieve stability?
    They interact by sharing, donating, or receiving electrons, forming chemical bonds.
  • What are the two main types of chemical bonds that achieve stability?
    Ionic bonds (transfer of electrons) and covalent bonds (sharing of electrons).
  • What is an ionic bond?
    A bond formed by the transfer of electrons between atoms, resulting in oppositely charged ions attracting each other.
  • What is a covalent bond?
    A bond formed by the sharing of electrons between atoms to fill their valence shells.
  • What is the difference between polar and nonpolar covalent bonds?
    Polar covalent bonds share electrons unequally, creating partial charges; nonpolar covalent bonds share electrons equally.
  • What is electronegativity?
    The ability of an atom to attract shared electrons in a covalent bond.
  • Which atoms are highly electronegative?
    Oxygen and Nitrogen are highly electronegative atoms.
  • What does a large difference in electronegativity between two atoms indicate?
    It usually indicates an ionic bond due to electron transfer.
  • What is the difference in electronegativity between hydrogen (2.1) and chlorine (3.0), and what type of bond does it form?
    Difference is 0.9, which forms a polar covalent bond.
  • How many bonds does carbon typically form and why?
    Carbon has 4 valence electrons and forms 4 covalent bonds to complete its octet.
  • What is the role of phosphate (P) in biological molecules regarding bonding?
    Phosphorus can form 3 to 5 covalent bonds, often forming double or triple bonds in biological molecules.
  • What is oxidation in redox reactions?
    Oxidation is the loss or donation of electrons by an atom or molecule.
  • What is reduction in redox reactions?
    Reduction is the gain or acceptance of electrons by an atom or molecule.
  • What is the significance of chemical bonds in biomolecules?
    Chemical bonds determine the structure, polarity, and function of biomolecules.