AP Chemistry - Unit 2: Compound Structure and Properties

Ionic

Electrons are transferred (metal and non-metal)

Covalent

Electrons are shared (non-metals)

Metallic

Electrons not associated with a single atom; Sea of Electrons

Delocalized electrons are…

mobile, constantly moving between atoms

If the difference in electronegativity is equivalent or similar (<0.4), the bond is…

Nonpolar covalent

If the difference in electronegativity is moderate/decent (>0.4), the bond is…

Polar covalent

If the difference in electronegativity is very large, the bond is…

Ionic

When electrons are shared unequally, a __ results.

Bond dipole

The greater the electronegativity, the polar the bond.

more

Which bond has the fewest shared electrons, the weakest bond, and the longest bond?

Single bond

Which bond has the most shared electrons, the strongest bond, and the shortest bond?

Triple bond

Electrostatic attraction is…

the force that pulls objects with opposite electrical charges together.

Coulomb's Law:

Larger ion charge -> larger force of attraction

Greater distance between charges -> smaller force of attraction

Lattice energy __ when ion c̲h̲a̲r̲g̲e̲s̲ increase.

increases

Lattice energy __ when ion s̲i̲z̲e̲s̲ increase.

decreases

Ionic solids are typically…

very strong crystalline structures held together with repeating positive and negative charges

To conduct electricity, a substance must have…

charged particles, particles that are free to move

Metal properties:

Good conductors, malleable, ductile (pulled in a wire)

Substitutional alloys form between atoms of ___ radii

similar, comparable

Interstitial alloys form between atoms of ___ radii

different

Elements in the period and below can expand their octets by utilizing the d orbital.

3rd (excluding 3s)

Structures used to describe a molecule with multiple equivalent Lewis structures are called…

resonance structures

Formal charges are calculated by…

Valence electrons - (lone pair electrons + 1/2(shared electrons))

The best Lewis structure has…

the fewest charges, negative charge on the most electronegative atom

If filling the octet of the central atom results in a negative charge on the central atom and a positive charge on the most electronegative outer atom…

…don't fill the octet of the central atom.

Is it more important to…
A. Fill the octets of every atom
or
B. Place a negative charge on the most electronegative atom and a positive charge on the least

B.

Electron pairs _ each other.

repel

The electron-domain geometry with 2 electron domains is…

Linear

The electron-domain geometry with 3 electron domains is…

Trigonal planar

The electron-domain geometry with 4 electron domains is…

Tetrahedral

The electron-domain geometry with 5 electron domains is…

Trigonal pyramidal

The electron-domain geometry with 6 electron domains is…

Octahedral

Electron-domain geometry vs. Molecular geometry

Electron-domain geometry includes unbonded electrons, while molecular geometry doesn't

If only 2 atoms are bonded together, the molecule will be…

linear

If all electron domains are bonding in a molecule with 3 domains, the molecule is…

Trigonal planar

If one electron domain is a nonbonding pair in a molecule with 3 domains, the molecule is…

Bent

If all electron domains are bonding in a molecule with 4 domains, the molecule is…

Tetrahedral

If one electron domain is a nonbonding pair in a molecule with 4 domains, the molecule is…

Trigonal pyramidal

If two electron domains are nonbonding pairs in a molecule with 4 domains, the molecule is…

Bent

If all electron domains are bonding in a molecule with 5 domains, the molecule is…

Trigonal bypyramidal

If one electron domain is a nonbonding pair in a molecule with 5 domains, the molecule is…

Seesaw

If two electron domains are nonbonding pairs in a molecule with 5 domains, the molecule is…

T-shaped

If three electron domains are nonbonding pairs in a molecule with 5 domains, the molecule is…

Linear

If all electron domains are bonding in a molecule with 6 domains, the molecule is…

Octahedral

If one electron domain is a nonbonding pair in a molecule with 6 domains, the molecule is…

Square pyramidal

If two electron domains are nonbonding pairs in a molecule with 6 domains, the molecule is…

Square planar

True or False: If a large molecule possesses some polar bonds, the entire molecule is automatically polar.

False

How do you find the overall dipole movement for a molecule?

By adding the individual bond dipoles together

Molecules where the central atom is symmetrically surrounded by identical atoms are…

Nonpolar

Major shapes (linear, trigonal planar, octahedral, etc.) with identical surrounding atoms are…

Nonpolar

Molecules with lone pairs, with the exception of linear and square planar molecules, will be…

Polar

If an atom absorbs a small amount of energy, it can…

promote an electron from the 2s to the 2p orbital

Combining the s and p orbitals yields…

2 equal energy orbitals that are hybrids of the s and p orbitals

2 electron domains lead to a ___ hybrid orbital.

sp

3 electron domains lead to a ___ hybrid orbital.

sp²

4 electron domains lead to a ___ hybrid orbital.

sp³

Sigma bonds (σ) are characterized by…

Head-to-head overlap, cylindrical symmetry of electron density around the internuclear axis

Pi bonds (π) are characterized by…

Side-to-side overlap, electron density above and below the internuclear axis

Single bond are always bonds.

sigma

In a multiple bond, one bond is always…

sigma

In a multiple bond, one bond is always sigma, while the rest are…

pi

The predicted bond angle of a molecule with a linear electron-domain geometry is…

180°

The predicted bond angle of a molecule with a trigonal planar electron-domain geometry is…

120°

The predicted bond angle of a molecule with a tetrahedral electron-domain geometry is…

109.5°

The predicted bond angle on the equatorial position of a molecule with a trigonal bypyramidal electron-domain geometry is…

120°

The predicted bond angle on the axial position of a molecule with a trigonal bypyramidal electron-domain geometry is…

90°

The predicted bond angle of a molecule with a octahedral electron-domain geometry is…

90°

Double and triple bonds place greater electron density on one side of the central atom than single bonds do. Therefore, they will have a _ bond angle between them and other bonds.

greater

Nonbonding pairs are physically __ than bonding pairs.

larger

Nonbonding pairs have greater repulsions than bonding pairs; this _ their bond angles.

decreases

Electronegativity _ from left to right across a row.

increases

Electronegativity _ from top to bottom across a row.

decreases

What are the three electrostatic interactions that govern chemical bonding?

Attractions between electrons and nuclei, repulsions between electrons, repulsions between nuclei

On a potential energy diagram, the __ is the ideal energy and internuclear distance level.

trough, valley

On a potential energy diagram, the distance the trough has from the x-axis is the…

bond energy

On a potential energy diagram, the distance the trough has from the y-axis is the…

distance between atoms

Bond energy is the…

energy required to break a bond

Internuclear distance is the…

distance between atoms