Chemistry Chapter 3: Bonding and Chemical Interactions (3 Stars) Flashcards
Chemical bonds can be _____ or covalent.
ionic
Elements will form _____ to attain a noble gas-like electron configuration.
bonds
The octet rule states that elements will be most stable with ____ valence electrons.
eight
Elements with an incomplete octet are stable with fewer than eight electrons and include H, He, __, Be, and B.
Li,
Elements with an expanded octet are stable with more than eight electrons and include all elements in period _ or greater.
3
Compounds with a(n) ____ number of electrons cannot have eight electrons on each element.
odd
A(n) _____ bond is formed via the transfer of one or more electrons from an element with a relatively low ionization energy to an element with a relatively high electron affinity.
ionic
Ionic bonds occur between elements with _____ differences in electronegativity (ΔEN ____ ), usually between metals and nonmetals.
large
(ΔEN > 1.7)
A positively charged ion is called a ____. A negatively charged ion is called an _____.
cation.
anion.
The resulting electrostatic attraction between the ions causes them to remain in _______ proximity , forming the bond.
close proximity
Ionic compounds form ______ —large, organized arrays of ions.
crystalline lattices
Ionic compounds tend to dissociate in ____ and other _____ solvents.
water
polar
Ionic solids tend to have ____ melting points.
high
A _____ bond is formed via the sharing of electrons between two elements of similar electronegativities.
covalent
Bond order refers to whether a covalent bond is a single bond, double bond, or triple bond. As bond order increases, bond strength ______, bond energy increases, and bond length ______.
increases
decreases.
Nonpolar bonds result in molecules in which both atoms have exactly the _____ electronegativity;
same
there is a very small difference in electronegativity between the atoms (ΔEN < 0.5), even though they are technically slightly polar.
Polar bonds form when there is a ______ difference in electronegativities but not enough to transfer electrons and form an ionic bond.
significant
(ΔEN = 0.5 to 1.7),
In a polar bond, the more electronegative element takes on a partial negative charge, and the less electronegative element takes on a partial positive charge.
Coordinate covalent bonds result when a single atom provides _____ bonding electrons while the other atom does not contribute any; coordinate covalent bonds are most often found in Lewis acid–base chemistry.
both
Lewis dot symbols are a _____ representation of an atom’s valence electrons.
chemical
Drawing a complete Lewis dot structure requires a balance of valence, _____, and nonbonding electrons in a molecule or ion.
bonding
Formal charges exist when an atom is surrounded by more or fewer valence electrons than it has in its _____ state (assuming equal sharing of electrons in a bond).
neutral
For any molecule with a π (pi) system of electrons, _____ structures exist; these represent all of the possible configurations of electrons—stable and unstable—that contribute to the overall structure.
resonance
The valence shell electron pair repulsion (VSEPR) theory predicts the three-dimensional molecular geometry of ______ bonded molecules. characteristic geometries.
covalently
In this theory, electrons—whether bonding or nonbonding—arrange themselves to be as far apart as possible from each other in three-dimensional space, leading to characteristic geometries.
Nonbonding electrons exert more ______ than bonding electrons because they reside closer to the nucleus.
repulsion
Electronic geometry refers to the position of all electrons in a molecule, whether bonding or nonbonding. Molecular geometry refers to the position of only the ______ pairs of electrons in a molecule.
bonding pairs
The polarity of molecules is ______ on the dipole moment of each bond and the sum of the dipole moments in a molecular structure.
dependent
Nonpolar molecules may contain nonpolar bonds, or polar bonds with _____ moments that cancel each other.
dipole
σ and π bonds describe the patterns of _____ observed when molecular bonds are formed.
overlap
Sigma (σ) bonds are the result of ______ overlap.
head-to-head
Pi (π) bonds are the result of the overlap of two _____ electron cloud densities.
parallel
Intermolecular forces are ______ attractions between molecules. They are significantly weaker than covalent bonds (which are weaker than ionic bonds).
electrostatic
London dispersion forces are the _____ interactions, but are present in all atoms and molecules.
weakest interactions, but are present in all atoms and molecules.
As the size of the atom or structure increases, so does the corresponding London dispersion force.
______ interactions, which occur between the oppositely charged ends of polar molecules, are stronger than London forces; these interactions are evident in the solid and liquid phases but negligible in the gas phase due to the distance between particles.
Dipole–dipole
______ are a specialized subset of dipole–dipole interactions involved in intra- and intermolecular attraction;
Hydrogen bonds
hydrogen bonding occurs when hydrogen is bonded to one of three very electronegative atoms— fluorine, oxygen, or nitrogen
