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General Biology: Atoms, Elements, 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.
  • How many electrons make a valence shell stable in the first three shells?
    Shell 1 is stable with 2 electrons; Shell 2 and Shell 3 are stable with 8 electrons each.
  • What is the atomic number of an element?
    The atomic number is the number of protons in an atom and defines the 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 a full valence shell of 8 electrons, achieving stability.
  • What are the three main subatomic particles and their charges?
    Protons (+1 charge), Neutrons (0 charge), and Electrons (-1 charge).
  • What is a covalent bond?
    A covalent bond is formed when two atoms share electrons to complete 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 causes polarity in covalent bonds?
    Differences in electronegativity between atoms cause unequal sharing of electrons, resulting in polarity.
  • What is electronegativity?
    Electronegativity is an atom's ability to attract shared electrons in a bond.
  • What is an ionic bond?
    An ionic bond forms when electrons are transferred from one atom to another, creating oppositely charged ions that attract.
  • How do atoms achieve stability through bonding?
    Atoms interact by sharing, donating, or receiving electrons to fill their valence shells and become stable.
  • What is the difference in electronegativity that typically indicates an ionic bond?
    A difference greater than 1.7 in electronegativity usually indicates an ionic bond.
  • What is the chemical formula for glucose and what does it indicate?
    Glucose is \(C_6H_{12}O_6\), indicating 6 carbon, 12 hydrogen, and 6 oxygen atoms.
  • How many bonds does carbon typically form and why?
    Carbon has 4 valence electrons and typically forms 4 covalent bonds to complete its valence shell.
  • What is the significance of hydrogen, oxygen, carbon, and nitrogen in biology?
    These elements (HONC) are the primary building blocks of biomolecules due to their bonding properties.
  • What is oxidation and reduction in redox reactions?
    Oxidation is the loss of electrons; reduction is the gain of electrons.
  • What type of bond is found in hydrochloric acid (HCl) based on electronegativity values H=2.1 and Cl=3.0?
    HCl has a polar covalent bond due to an electronegativity difference of 0.9.
  • What is the role of valence electrons in chemical bonding?
    Valence electrons are involved in forming chemical bonds to achieve full outer shells and stability.
  • What is the structure and function of the nucleus in an atom?
    The nucleus contains protons and neutrons and holds most of the atom's mass.