CHEM 261: CHAPTER 1
86 Cards in this Set
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atomic number
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number of protons
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mass number
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number of protons and neutrons
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isotopes
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atoms with the same number of protons but different numbers of neutrons.
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atomic weight
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average mass of atoms of an element
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Louis de Broglie
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1923- suggested that electrons have wave and particle properties
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Schrodinger
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created the wave equation which describes the energy of an electron and the volume of spaces where they are likely to be found.
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1s orbital is _____ (shape) with __(#) nodes
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1s orbital is spherical with 0 nodes
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2s orbital is _____(shape) with __(#) nodes
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2s orbital is spherical with 1 node
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node
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where the probability of finding an electron is 0
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2p orbital has __ orbitals of ___ energy, called ______. They are aligned along the _, _, and _ axis
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2p orbital has 3 orbitals of equal energy, called degenerate. They are aligned along the x, y, and z axis.
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A d orbital starts at __shell and has _ orbitals.
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A d orbital starts at 3rd shell and has 5 orbitals.
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Aufbau Principle
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orbitals are filled from lower to higher energy
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Pauli Exclusion Principle
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Maximum of 2 electrons per orbital
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Hund's Rule
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Orbitals of equal energy (degenerate) receive one electron until all the orbitals have one and then the electrons begin to pair up in the orbitals.
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Orbitals closer to the nucleus are ____ in energy
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lower
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Electrons have a spin of ___ and ___ which gives rise to a small __________
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+1/2 and -1/2 which gives rise to a small magnetic field
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Repulsion between electrons is reduced when they have ________
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opposite spins
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Electrons are paired when they _________
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have opposite spins and occupy the same orbit
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core electrons
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electrons in the filled shells; all non valence electrons
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valence electrons
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electrons in the outer, unfilled shell.
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Electronegativity
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a measure of the atom's attraction for outer bonding electrons. Increases up the columns and down the rows.
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Electronegativity increases with ______ charge on the nucleus and with _____ distance between the nucleus and electrons.
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Electronegativity increases with increasing charge on the nucleus and with decreasing distance between the nucleus and electrons.
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Carbon is _____ in electronegativity
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intermediate
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GN Lewis created the ____ ___
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octet rule
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Octet rule
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atoms will donate, accept or share electrons in order to achieve a filled outer shell.
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A difference of ____ in electronegativity between 2 atoms results in an ionic bond
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greater than 1.5
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A difference of ___ in electronegativity between 2 atoms results in a covalent bond.
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less than 1.5
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__ -__ = nonpolar covalent bond
__-__= polar covalent bond
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0-0.5: nonpolar covalent bond
0.5-1.5: polar covalent bond
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ionic bond
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one or more electrons are completely transferred from one atom to another, creating ions which are then held together by the electrostatic attractions.
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Covalent bond
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one or more electrons is shared by atoms and atomic orbitals merge into shared or molecular orbitals
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Carbon usually forms ____ bonds
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covalent
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dipole
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this exists in a polar bond and their is a negative and positive end. the size is indicated by the dipole moment
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empirical formula
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gives the type of atoms and the ration of atoms in a compound
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molecular formula
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gives the type and actual number of atoms in a molecule
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structural formula
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gives the type, number and actual order or structure of the molecule
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Lewis structures use ___ for electrons
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dots
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Line-bond formulas (Kekule stuctures) use a ___ to represent two electrons bonding (a shared pair)
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line
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Condensed formulas
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bonds are not always shown and atoms of the same type bonded to another atom are grouped together
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polygon formulas
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used to represent cyclic compounds. Each point represents a carbon and is assumed to have enough H bonded to it to give it 4 bonds.
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Skeletal Formulas
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- focused on C, H atoms omitted
- often zig zag, each point is a C
- double and triple bonds drawn with extra lines
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Heteroatoms in skeletal formulas have sufficient ______to complete each atom's octet.
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unshared pairs of electrons
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wavefunction
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ψ a mathematical function that describes an electrons position and energy
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wavefunction is characterized by quantum numbers: __, ___, and __
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n, l, and m_l
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the sign of a wavefunction has ___
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no physical meaning
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ψ^2
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describes the probability of finding an electron at a particular point
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wave properties:
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constructive or destructive
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when wave functions are constructive, the wave functions are ______ and there is a ____ interaction
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when wave functions are constructive, the wave functions are inphase and there is a bonding interaction
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when wave functions are destructive, they are ____________ and there is ___________
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when wave functions are destructive, they are out of phase and there is antibonding.
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conservation of orbitals
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the number of orbitals created equals the number of orbitals combined
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combining orbitals constructively results in ___-phase _________
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combining orbitals constructively results in in-phase bonding
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combining orbitals destructively results in ___-phase _________
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combining orbitals destructively results in out-of-phase antibonding
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LCAO
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Linear combination of atomic orbitals= molecular orbitals
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A bonding orbital has ___ electron density between the nuclei
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high
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An antibonding orbital has _____ between the nuclei
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a node (0 electron density)
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sigma bond is _____ symmetrical
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cylindrically
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3 Rules for Assigning Hybridization State
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1. All lone pairs live in hybrid orbitals
2. sigma bonds are formed by hybrid orbitals
3. pi bonds, radicals, and cations occupy unhybridized p orbitals.
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You can have a resonance structure when you have a charged atom next to an atom involved in a ___ bond.
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pi
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Resonance structures differ only in the position of ______ not ____
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electron pairs, not atoms
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In resonanace structures, only __ electrons and ___ electrons can move around, never ___ electrons
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pi electrons and unshared electrons can move around, never sigma electrons.
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Overall net charge of each resonance structure ___________
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must be the same
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A bronsted-lowry acid is
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a proton donor
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A bronsted-lowry base is
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a proton acceptor
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A strong Bronsted-Lowry acid is ___
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an acid that completely dissociated or ionized in water
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A weak Bronsted-lowry acid is
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an acid that only partially dissociates or ionizes in water
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Carboxylic Acids
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(RCO2H) have an --R group and an --OH group attached to the carbonyl group
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Carboxylic acids are ____ acids
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weak
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Amines
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R
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R-N-R
Named (R group 1)(R group 2)(R group 3) Amine
Primary/Secondary/tertiary - # of R groups
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Amines are weak ____
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bases
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If Ka is large, ____ are favored and the reacting acid is ____
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products are favored and the reacting acid is a strong acid
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If Ka is small, ____ are favored and the reacting acid is ____
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reactants are favored and the reacting acid is weak
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pKa=
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-logKa
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The lower the pKa, the ____ the acid
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stronger
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The higher the pKa, the ____ the acid and the _____ the base
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weaker the acid and the stronger the base
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Generally, strong acids have ___ conjugate bases and weak acids have ___ conjugate bases
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strong acids have weak conjugate bases and weak acids have strong conjugate bases.
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The ability of the conjugate base to stabilize a negative charge determines the ______ of the acid
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strength
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Anything that ____ the anion (A-) will increase the acidity of HA.
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Anything that stabilizes the anion (A-) will increase the acidity of HA.
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6 Factors that affect acidity and stabilize the anion
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1. Electronegativity of the atom carrying the charge (A-)
2. Size of the atom carrying the charge.
3. Hybridization of the atom carrying the charge.
4. Inductive (electron withdrawing or donating) effects of other nearby groups
5. Resonance stabilization of the charge
6. Solvation of…
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As electronegativity increases, the ____ increases
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acidity
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If the atom is more electronegative, the electrons are ____ tightly held and the atom is ___ willing to share those electrons and accept a proton and so it is a ______ base.
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If the atom is more electronegative, the electrons are more tightly held and the atom is less willing to share those electrons and accept a proton and so it is a weaker base.
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As the size of the atom increases, the acidity ____
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increases
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sp is ___ acidic than sp^2, which is ___ acidic than sp^3
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more, more
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The more s character in a hybrid orbital, the ____ the electrons are to the atom and the ____ acidic the atom/molecule
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The more character in a hybrid orbital, the closer the electrons are to the atom and the more acidic the molecule
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The anion is _____ stable when an electronegative atom or molecule is an adjacent group because it will ______ the electron density on the anion by dispersing the change through induction. Thus, the anion will be more _____.
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The anion is more stable when an electronegative atom or molecule is an adjacent group because it will decrease the electron density on the anion by dispersing the change through induction. Thus, the anion will be more acidic.
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Induction decreases with ____ distance from the atom losing a proton. Thus, as the distance decreases, the acidity __________.
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Induction deceases with increasing distance from the atom losing a proton. As the distance decreases, the acidity increases.
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Resonance _____ charge over multiple atoms and so it ____the energy of the structure. More equal resonance structures = ______ acidity.
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Resonance spreads charge over multiple atoms and so it lowers the energy of the sturcture. More equal resonance structures= higher acidity.
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Delocalization of electron density through resonance ____ the energy of the overall system and increases the _____
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Delocalization of the electron density through resonance lowers the energy of the overall system and increases the acidity.
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CHEM 261: CHAPTER 1