CH 2 vocab

Card Set Information

CH 2 vocab
2012-10-10 19:27:09
bio vocab

ch 2 bio vocab
Show Answers:

  1. What is an atom?
    The smallest unit that retains the chemical and physical properties of an element
  2. What is an element?
    Pure substance that cannot be broken down into simper substances by ordinary chemical or physical means
  3. What is a proton
    positive charged subatomic particle (has mass)
  4. what is a neutron
    no charge subatomic particle (has mass)
  5. what is an electron?
    negatively charged subatomic particle (has relatively no mass)
  6. what is an electron orbital?
    The region of space when the electrons "live" most of the time
  7. What is the shell model?
    • regions of space around the nucleus where electrons are found.
    • Shows the number of electrons in each orbital or just the valence electron shell
  8. What is a valence electron
    An electron in the outer-most energy level of an atom
  9. what is an Isotope
    A distinct form of the atoms of an element, with the same number of protons but different number of neutrons
  10. what is a molecule?
    A unit composed of atoms combinded chemically in fixed numbers and ratios
  11. what is are chemical bonds
    Link formed when atoms of reactive elements combine into molecules
  12. what is an ion?
    A positive or negative charged atom
  13. what is an ionic bond?
    Bond that results from electrical attractions between atoms that have lost or gained electrons
  14. what are polar and non-polar covalent bonds?
    • nonpolar covalent bonds have electrons shared equally
    • -characteristics of molecules that contain atoms of 1 element
    • polar covalent bonds share electrons unequally
    • -atom attracts electrons more strongly
  15. what is electronegativity
    The measure of an atom's attraction for the electrons it shares in a chemical bond with another atom
  16. What is a chemical formula?
    • The name of a molecule written in chemical shorthand
    • Ex. H2O
  17. What are hydrogen bonds?
    Noncovalent bond formed by unequal electron sharing between hydrogen atoms and oxygen, nitrogen, or sulfur atoms
  18. What are Van Der Waals forces?
    weak molecular attractions over short distances
  19. what does hydrophobic mean?
    nonpolar substances that are excluded by water and other polar molecules
  20. What does hydrophilic mean?
    Polar molecules that associate readily with water
  21. What is cohesion?
    The high resistance of water molecules to separation
  22. What is adhesion?
    the adherence of molecules to the walls of conducting tubes, as in plants
  23. what is surface tension?
    • The force that places surface water molecules under tension, making them more resistant to separation than underlying water molecules
    • Ex. When you do a bellyflop, you slap the water and you don't just fall through as if you were diving.
  24. what is a solvent?
    The water in a solution in which the hydration layer prevents polar molecules or ions from reassociating
  25. what is a chemical reaction?
    A reaction that occurs when atoms or molecules interact to form new chemical bonds or break old ones
  26. what are reactants?
    The atoms or molecules entering a chemical reaction
  27. What are products?
    An atom or molecule leaving a chemical reaction