chem ch 8 pt 2

Electronegativity

The ability of an atom to attract electrons to itself, as well as keep its own electrons.

Partial charges

When a covalent compound has an electro negativity difference between (0.4,1.6), the atom has partially positive and negative sides. It’s not fully spread out.

Intermolecular forces

Forces that between molecules. Ex. Dipole dipole, hydrogen bonding, London dispersion.

A strong bond implicates…

High boiling/melting point. Present in polar compounds, hydrogen bonds, and ionic bonds

Radius (up to down)

Increase, because # of shielding electrons (“n”) increases, and due to increased repulsion, electrons spread out.

Ionization energy

Energy requires to remove an electron from a neutral atom. Creates a positive ion.

Covalent connection to electronegativity

Since the EN of both atoms in a covalent compound is high, they want to steal others’ electrons while holding onto their own. This results in them sharing.

Valence

The combining capacity of each atom. (Empty electrons in an orbital)

Dipole

Partial separation of charge which exists when one side of the molecule has a partial positive and partial negative charge.!

Polarization

The process of repelling electrons of nearby atoms.

London forces are strong when…

Atomic numbers increase, because the amount of electrons increases and they can move a lot more.

London forces are significant for…

Noble gases and covalently bonded molecules. They are sometimes the only force between those.

Isoelectronic

The term for when the ionization energy becomes high for ions (previously atoms)—and they are close to having the noble gas configuration.

Electron affinity

Energy change when an electron is accepted

Lewis theory

1. Valence electrons play a key role in bonding

2. Sharing electrons = covalent

3. Transferring electrons = ionic

4. Goal is to have a stable electron configuration

Properties of ionic compounds

1. Grow crystal lattices

2. High melting points due to strong bonds

3. No special molecules

4. Conduct electricity when dissolved or melted

5. Neutral overall

6. Less reactive than their atoms

Dipole dipole force is shown…

Using a hashed line in a diagram.

How does water dissolve ionic compounds?

Water is a polar compound, so the strong charges of ionic compounds blend right in.

Octet electron deficieny

1. Beryllium (4)

2. Boron (6)

3. Aluminum (6)

Expanded octet

1. P

2. S

3. Cl

In the 3rd and 4th periods.

Structural isomers

Different atomic linkages, same formula.

Structural resonance

Same atomic linkages, same formula.

Resonance structural bonding…

Is an average of the resonance structures, and often, electrons bonds are spread out. (Ex. 1.5 shown with a straight and a dotted line)

VSPER

Foundation is that electrons (esp valence) repel each other and wanna be as further from each other as possible.

valence repulsion

LP > BP

Determining polarity

1. Electronegativity difference

2. Symmetry of molecule (tugging analogy)

remember vector arrows!!