PRELIM 02 - Structure and Bonding Flashcards
Most of the atom’s mass is in the __________
Nucleus
Most of the atom’s volume is in the __________
Electron cloud
According to this model, the exact location of the electron cannot be known
Quantum mechanical model
The probability that the electron will be in a certain region of space at a given instant
Electron density
Electrons do not circle around the nucleus in fixed orbits but rather, in __________
Orbitals
Are used to describe orbitals
Quantum numbers
4 types of quantum numbers
Principal, Azimuthal/Angular momentum, Magnetic, Electron spin
Describes the orbitals occupied by the atom’s electrons when they are all in the available orbitals with the lowest energy
Ground-state electron configuration
4 rules in electron configuration
Aufbau principle, Hund’s principle, Pauli’s exclusion principle, Heisenberg’s uncertainty principle
Are electrons below the outermost shell
Core electrons
Are electrons in the outermost shell
Valence electrons
An attractive force between two ions or between two atoms
Chemical bond
According to this rule, an atom is most stable if its outer shell is either filled or contains eight electrons
Octet rule
Bond formed as a result of electrostatic attraction between ions of opposite charge
Ionic bond
Compounds formed by ionic bonds
Ionic compound
Bond formed as a result of sharing electrons between two nuclei
Covalent bond
Compounds formed by covalent bonds
Molecular compounds
Measure of the ability of an atom to pull the bonding electrons toward itself
Electronegativity
A covalent bond between atoms with the same electronegativity
Nonpolar covalent bond
A covalent bond between atoms with different electronegativities
Polar covalent bond
A pair of equal and oppositely charged poles separated by a distance
Dipole
Measure of dipole
Dipole moment
Electron-dot structures
Lewis structure
Line-bond structures
Kekulé structure
Not an actual charge; used for bookkeeping of electrons
Formal charge
Omitting of the covalent bonds and listing atoms bonded to a particular carbon next to it
Condensed structure
Carbon atoms aren’t usually shown
Skeletal structures
A 3D structure that shows 3D shape
Perspective drawing
A 3D structure that shows bond angles accurately
Ball-and-stick model
A 3D structure that shows atoms in scale
Space-filling model
Geometry based on arrangement of atoms in a molecule
Molecular geometry
Geometry based on valence electron pairs
Electron pair geometry
A model for the prediction of molecular geometry based on the minimization of electron repulsion
Valence-shell electron-pair repulsion (VSEPR) model
Assumes that the electrons in a molecule occupy overlapping atomic orbitals of the individual atoms
Valence bond theory
Assumes the formation of molecular orbitals from the atomic orbitals
Molecular orbital theory
Head-on overlap of atomic orbitals; stronger
Sigma (σ) bond
Sideway overlap of atomic orbitals; weaker
Pi (π) bond
Atomic orbitals obtained when two or more nonequivalent orbitals of the same atom combine for covalent bond formation
Hybrid orbitals
Described a region in space in a molecule where electrons are most likely to be found
Molecular orbital
2 ways to combine atomic orbitals into molecular orbitals
Additive, Subtractive
Lower energy, bonding molecular orbital
Additive
Higher energy, antibonding molecular orbital
Subtractive
Occurs when an electron is shared by more than 2 atoms with π bonds
π Electron delocalization
Their special resonance relationship is indicated by the double-headed arrow between them
Resonance forms
Indicated vacant p orbital, single electron, or lone pair of electrons on atom Z
Asterisk (*)
Drawn between resonance forms
Double headed arrow
Indicated movement of electrons
Curly arrow
From electron-rich species
Tail
To electron-deficient species
Head
Double bonds separated by single bonds
Conjugation
Special kind of conjugation
Aromaticity
Bond lies in the plane of the paper
Normal bond
Bond extends backwards, away from the viewer
Dashed bond
Bond protrudes forward, towards the viewer
Wedged bond
