Bonding and Chemical Interactions Flashcards
Name some of the elements that are exceptions to the octet rule.
- Hydrogen
- Helium
- Lithium (stable with 2 e-)
- Beryllium (stable with 4 e-)
- Boron (stable with 6 e-)
- All elements in period 3 or greater, which can expand the valence shell to include more than 8 electrons by incorporating d-orbitals)
If the electron pair in a covalent bond is shared equally, the bond is _____.
Nonpolar (covalent)
If the electron pair in a covalent bond is shared unequally, it is ______.
Polar (covalent)
If both of the shared electrons are contributed by only one of the two atoms, the bond is called _______ covalent.
Coordinate
List some characteristics of ionic compounds.
- Very high melting and boiling points
- Dissolve readily in water and other polar solvents
- Good conductors of electricity in the aqueous state
- In the solid state, form a crystalline lattice
The number of shared electron pairs between two atoms is called the bond ____.
Order
How do the bond lengths compare in single, double, and triple bonds?
From longest to shortest: single > double > triple
How does the bond energy differ in single, double, and triple bonds?
From greatest energy to least energy: triple > double > single
What are the seven common diatomic molecules?
Hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine
Any bond between atoms with a difference in electronegativity less than ____ is generally considered nonpolar.
0.5
The electronegativity difference in polar covalent bonds ranges from ____ to ____.
0.5 to 1.7
The dipole moment of a polar bond or polar molecule is a vector quantity given by the equation p = __ __.
p = qd, where p is the dipole moment, q is the magnitude of the charge, and d is the displacement vector separating the two partial charges.
Does a Lewis acid accept or donate a pair of electrons?
Accepts
If Lewis structures show the same bond connectivity and differ only in the arrangement of the electron pairs, these structures represent different ____ forms of a single compound.
Resonance
True or false: The Lewis structure that minimizes the number and magnitude of formal charges is usually the most stable arrangement of the compound.
True
True or false: When drawing out the backbone of a compound in a Lewis dot structure, the least electronegative atom is the central atom.
True
What elements typically occupy a terminal position in a Lewis dot structure?
Hydrogen and the halogens F, Cl, Br, and I (usually)
The difference between the number of electrons assigned to an atom in a Lewis structure and the number of electrons normally found in that atom’s valence shell is the ____ ____.
Formal charge
Give an equation used to determine formal charge.
formal charge = V - # of nonbonding electrons - number of bonds
(where V is the number of valence electrons in the neutral atom)
True or false: In general, the more stable the Lewis structure, the more it contributes to the character of the resonance hybrid.
True
One can use formal charge to assess the stability of resonance structures according to the following guidelines: (Study Card)
- A Lewis structure with small or no formal charges is preferred over a Lewis structure with large formal charges.
- A Lewis structure with less separation between opposite charges is preferred over a Lewis structure with a large separation of opposite charges.
- A Lewis structure in which negative charges are placed on more electronegative atoms is more stable than one in which the negative formal charges are placed on less electronegative atoms.
Electronic geometry describes the spatial arrangement of what?
It describes the spatial arrangement of ALL pairs of electrons around the central atom, including both the bonding and the lone pairs.
Does molecular geometry describe the spatial arrangement of bonding or nonbonding pairs around the central atom?
Bonding
The _____ number is the number of of atoms that surround and are bonded to a central atom.
Coordination
True or false: the presence of bond dipoles will result in a molecular dipole.
False. A compound with polar bonds may be polar or nonpolar, depending upon the spatial arrangement of the polar bonds in the molecule.
Rank the common intermolecular forces in order from strongest to weakest.
- Hydrogen bonding
- Dipole-dipole interactions
- Dispersion forces (aka London forces or van der Waals forces)
Which electronegative elements are capable of forming hydrogen bonds?
Nitrogen, oxygen, and fluorine
