MCAT Gen Chem 1.1

  1. Metals always form _______.
  2. Non-metals always form _______.
  3. Cations are _______ than their neutral counterparts.
  4. Anions are _______ than their neutral counterparts.
  5. Metals
    Very large atoms with loosely held electrons...Form cations, are lustrous, ductile, malleable, and excellent conductors of both heat and electricity...they are usually only involved in ionic bonds.
  6. Non-metals
    Smaller atoms with loosely held electrons...Form anions, have much lower melting points than metals, and with very few exceptions, only nonmetals form covalent bonds.
  7. Large atom characteristics
    Larger atoms are better at stabilizing charges, form weaker pi bonds, and have d orbitals where they can "stash" extra electrons.
  8. Alkali metals
    Group 1, 1 electron in outer level, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium
  9. Alkaline earth metals
    Metallic elements in group 2 of the periodic table which are harder than the alkali metals and are also less reactive.
  10. Lanthanides
    The first of the two rows below the main part of periodic table. usually used in alloys, soft, malleable, shiny and good electrical conductors.
  11. Actinides
    In the 2nd row of transition metals, radioactive, unstable, do not occur in nature.
  12. Periodic table blocks
    Image Upload 2
  13. Electron Affinity
    • The amount of energy released when an electron is added to a neutral atom or molecule to form a negative ion.
    • X + eāˆ’ ā†’ Xāˆ’

    Image Upload 4

    It increases from left to right and from bottom to top
  14. Electronegativity
    The ability of an atom to attract electrons when the atom is in a compound.

    Image Upload 6

    It increases from left to right and from bottom to top
  15. Ionization Energy
    The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms or ions. Large atoms or molecules have a low ionization energy, while small molecules tend to have higher ionization energies.

    Image Upload 8

    It increases from left to right and from bottom to top
  16. Atomic Radius Trends
    Image Upload 10

    Atomic radius gets larger from right to left and top to bottom.
  17. Metallic Character Trends
    Image Upload 12

    Increases from right to left and top to bottom
  18. Metallic characteristics
    BIG and low low ionization energy
  19. First Quantum Number
    "n" (the principle quantum number)

    Gives the shell (i.e. Valence electrons are in the outermost "shell") and is approximately equal to the relative energy of electrons in that shell.
  20. Second Quantum Number
    "Image Upload 14" (the azimuthal quantum number)

    • Gives the subshell: has values of 0,1,2,3 and from this were know the shape:
    • 0=S ; 1=P ; 2=d ; 3=f
  21. Third Quantum Number
    "mImage Upload 16" (the magnetic quantum number)"the magnetic quantum number"

    Gives the orbital; has a value of -Image Upload 18 to Image Upload 20 (from the azimuthal quantum number)

    The orbital is the portion of the subshell where an electron is most likely to be found (i.e., which "dumbbell" of a p subshell)
  22. Fourth Quantum Number
    "ms" (the electron spin quantum number)

    Gives the spin which is either +1/2 or -1/2 (Positive is up arrow or negative is down arrow)
  23. Heisenberg uncertainty principle
    States a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known.

    The more precisely one property is measured, the less precisely the other can be controlled, determined, or known. You can know it's momentum, or where it's at, but you can't know both at the same time.
  24. Pauli exclusion principle
    No two electrons in a single atom can have the same four quantum numbers; if n, Image Upload 22, and mImage Upload 24 are the same, ms must be different such that the electrons have opposite spins, and so on.
  25. The Work Function
    If you bombard certain metals with energy, you can cause the ejection of an electron from their outermost shell (i.e. valence electron). The amount of energy required to do this is called the "work function."

    This is not the same as the Ionization energy because that refers to only lone atoms in a gaseous state. The work function refers to the valence electrons being ejected from the surface of a metal.
  26. Work Function formula
    KE = E – Image Upload 26

    • Image Upload 28 - work function variable
    • KE - of the ejected electron
    • E - amount of energy added


    E = hf

    • E - energy of a photon
    • h - Planck's constant
    • f - frequency
  27. Alpha Decay
    A He nucleus (2 neutrons and 2 protons) are ejected
  28. Beta Decay
    Neutron is changed into a proton (with the ejection of an electron)
  29. Electron Capture
    A proton is changed into a neutron via capture of an electrion
  30. Positron Emission (beta+ decay)
    A proton is changed into a neutron (with expulsion of a positron)
  31. Calculating Percent Mass
    Mass of one element divided by the total mass.
  32. Deriving a formula from percent mass
    • 1. Change the percent for each species into grams by assuming 100g. (i.e. 17% = 17g)
    • 2. Convert the grams of each species into moles by dividing by molar mass.
    • 3. Look at the element with the lowest number of moles. Calculate approximately how many times it will divide into each of the other molar amounts for each of the other elements--this number is the subscript for each element in the empirical formula. If the subscripts are not at their lowest common denominator, reduce to get the empirical formula.
  33. How to determine moles from mL
    m = V * P

    mass (g) = volume (cm3 or mL) * density (g/cm3)

    Then divide mass by molecular weight to get moles.
  34. What is a coordination compound?
    When one atom donates both electrons to a covalent bond with another atom with a + charge.

    Complex usually has a metal center.

    Most common example is NH3
  35. What characteristic determines how polar a hydride will be?

    The more electronegative, the stronger the polarity.
Card Set
MCAT Gen Chem 1.1