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66 Cards in this Set
- Front
- Back
A(n) _____ _____ gives the number of protons in the atom's nucleus.
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atomic number (z)
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A(n) _____ ____ gives the total of protons plus neutrons in an atom's nucleus.
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mass number (A)
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Atoms with the same atomic number but different mass number are _____.
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isotopes
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The weighted average mass in atomic mass units (amu) of an element's naturally occuring isotopes is called the element's _____ _____.
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atomic mass
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According to the quantum mechanical model, the behavior of a specific e- in an atom can be described by a(n) _____ _____.
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wave equation
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In the most common implentation, wavefunctions correspond to atomic orbitals called _____.
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psi
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_____ in three dimensional space describes the volume of space around a nucleus that an e- is most likely to occupy.
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psi squared
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The _____ _____ _____ determines the spatial orientation of the angular momentum (describes where the orbits are in space)
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magnetic quantum number (mL)
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The _____ _____ _____ takes on positive integers starting with one. (wavefunction question)
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principal quantum number (n)
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The _____ _____ _____ _____ _____ determines the angular momentum of the e- as it moves in an orbital
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orbital angular momentum quantum number (L)
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_____ tells us the shape of the orbital.
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L
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The different values of L are given _____ rather than _____.
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letters, numbers
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An atom's highest quantum number determines its _____ _____.
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valence shell
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The _____-orbitals are spherical with the nucleus in the center.
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s
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The _____-orbitals are dumbbell shaped.
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p
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The Px orbital is pictured _____.
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diagonally
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The Py orbital is pictured _____.
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horizontally
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The Pz orbital is pictured _____.
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vertically
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On a p-orbital, nodes are _____.
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a region of 0 e- density.
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The 3 e- configuration rules?
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- Aufbau's principle
- Pauli exclusion principle - Hund's rule |
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What is the Pauli exclusion principle?
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Only two e- may occupy an orbital and with opposite spins.
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What's the Aufbau principle?
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Lowest energy orbitals fill up first in this order:
1s->2s->2p->3s->3p->4s->3d |
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What is Hund's Rule?
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If two or more empty orbs of equal energy are available, one e- occupies each with spins parallel until all orbitals are half full.
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Explain valance bond theory.
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A covalent bond forms when two atoms approach each other closely and a singly occupied orbital on one atom overlaps the other atom.
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What is the bond formed when two singly occupied orbitals overlap?
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sigma bond
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What is the bond angle of the tetrahedron?
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109.5º
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Why are the lobes asymmetrical in an sp3 orbital?
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The lobes of the p-orbital are + and -. The positive p lobe adds to the s-orbital but the negative subtracts.
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The advantage of the asymmetric sp3 lobes?
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It can overlap more effectively with an orbital from another atom when it forms a bond.
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The meaning of the sp3 superscript?
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Tells how many p-orbitals combine to show the hybrid.
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Ethylene carbons can be tetravalent only if they share _____ e- and are linked by a _____ _____.
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four, double bond
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Ethylene is _____ and has bond angles of approximately _____.
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planar, 120º
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Ethylene is an _____ system, so it has sp2 hybrid orbitals, which is when:
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unsaturated, the 2s orbital combines with only two of the three available 2p orbitals, with one 2p orbital remaining unchanged.
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In ethylene, the three sp2 orbitals lie on a plane at angles of _____ to one another, with the remaining p-orbital _____ to the sp2 plane.
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120º, perpendicular
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In ethylene, when two sp2 hybridized carbons approach each other:
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they form a sigma bond by sp2-sp2 head on overlap.
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In ethylene, at the same time as the sp2 sigma bonds, the unhybridized p-orbitals do what?
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they approach each other with the correct geometry for a sideways overlap, leading to the formation of a π bond.
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In ethylene, the combination of the sigma bond and π bond results in the sharing of _____ _____ and a _____ _____ _____.
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4 e-, carbon-carbon double bond
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Carbon can form triple bonds by sharing _____ e-.
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six
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What happens in sp hybrid orbitals?
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Two sp orbitals result, and two p-orbitals remain unchanged.
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In acetylene, in an sp hybrid, a carbon 2s orbital hybridizes with only a _____ _____ orbital.
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single p
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In acetylene, the two sp hybrid orbitals are oriented _____ away from each other.
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180º
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In acetylene, when two sp hybridized molecules approach each other, sp hybrid orbitals on each carbon overlap head on to form a strong _____ _____ _____.
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sp-sp sigma bond
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In acetylene, following the formation of the sp-sp sigma bond, the _____ orbitals from carbon form a _____ _____ _____ by sideways overlap and the _____ orbitals overlap similarly to form a _____ _____ _____.
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pz, pz-pz π bond, py, py-py π bond
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In acetylene, once the first three hybridized orbitals are bonded, what becomes of the two remaining sp hybrid orbitals?
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they each form a sigma bond with hydrogen to complete the acetylene molecule.
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In acetylene, the net effect is the sharing of _____ e- and the formation of a _____ _____ _____.
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6, carbon-carbon triple bond
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What is CH3NH2?
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Methylamine. Derivative of NH3 and responsible for odor of rotting fish. Bleh.
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What's so special about the geometry of CH3NH2?
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Methylamine's experimentally measured H-N-H bond angle and C-N-H bond angle are very close to 109.5º...very close to tetrahedral bond angle of methane.
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What do we assume about the N bonds in methylamine?
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That N hybridizes to form form sp3 orbitals, just like carbon.
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What's so cool about phosphorus and sulfur, hm?
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they can accommodate more than an octect to form more covalent bonds
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How many bonds can P form?
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5 bonds
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How many bonds can S form?
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4 bonds
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What does molecular orbital theory describe?
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It describes covalent bond formation arising from a mathematical combination of atomic orbital to form molecular orbitals.
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And what do molecular orbitals describe?
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a region of space where electrons are most likely to by found
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if you take two singly-occupied 1s orbitals of H atoms and combine them to form molecular orbitals, you can get _____.
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addition
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What must you do for a subtractive combination of atomic orbitals?
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add the opposite phases
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The additive combination is _____ _____ _____ than the atomic orbitals.
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lower in energy
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The subtractive combination cannot have electrons where?
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in the central bonding region because there's a node
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What's another term for additive combinations?
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sigma-bonding
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What's another term for subtractive combinations?
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sigma-antibonding
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The additive combination is _____ _____ _____ than the atomic orbitals.
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lower in energy
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The subtractive combination cannot have electrons where?
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in the central bonding region because there's a node
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What's another term for additive combinations?
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sigma-bonding
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The additive combination is _____ _____ _____ than the atomic orbitals.
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lower in energy
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The subtractive combination cannot have electrons where?
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in the central bonding region because there's a node
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What's another term for subtractive combinations?
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sigma-antibonding
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What's another term for additive combinations?
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sigma-bonding
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What's another term for subtractive combinations?
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sigma-antibonding
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