Chemistry shape structure and bonding

What are the particles, arrangement, and bonding of a 3D covalent solid?

3D covalent solids are made up of atoms, arranged in a 3D network structure, held together by strong directional covalent bonds.

What are the particles, arrangement, and bonding of a 2D covalent solid?

2D covalent solids are made up of atoms, arranged in flat 2D sheets stacked on top of one another. The atoms in the flat sheets are held together by strong directional covalent bonds, and the flat sheets are held together by weak intermolecular forces of attraction.

What are the particles, arrangement, and bonding of an ionic solid?

Ionic solids are made up of ions (name cation and anion), arranged in an alternating 3D lattice structure, held together by strong directional ionic bonds.

What are the particles, arrangement, and bonding of a metallic solid?

Metallic solids are made up of metal atoms, arranged in a 3D lattice structure, held together by strong non-directional metallic bonds.

What are the particles, arrangement, and bonding of a molecular solid?

Molecular solids are made up of molecules, arranged in a regular pattern, held together by weak intermolecular forces of attraction.

Which side of the periodic table forms what type of ion?

Metals (left) form positive ions, non-metals (right) form negative ions

Where does the staircase start and end?

Between B and Al, down to between Po and At

How to know if a solid is an ionic solid

Bonding between a metal and a non-metal atom

How to know if a solid is a metallic solid

Bonding between 2 metal atoms

How to know if a solid is a molecular solid

Bonding between molecules (multiple of an element)

How to know if a solid is a covalent solid

Bonding between non-metal atoms

What is electronegativity

The ability of an atom to attract bonding electrons

What is the most electronegative atom?

Fluorine (F)

What is a polar covalent bond?

When the bonding electrons are unequally shared between the two atoms in the bond (spend more time closer to the more electronegative atom). If the two atoms have diff E.N then the more electronegative atom will attract the shared electrons more strongly. Results in a dipole

What is a non-polar covalent bond?

When the bonding electrons are equally shared between the atoms in the bond (same amount of time spent with each atom, same E.N). No dipole

Polar bonds come from differences in electronegativity between atoms, but there are 2 exceptions to this, what are they?

Symmetry (no side of the molecule has more negative or positive charge than another side, no lone pairs) - cancels out dipole

Size of dipole - equal sizes will cancel

Steps to explain/justify polarity

LEBSPSD

1. LEBS: Lewis diagram, Electron clouds - how many regions negative charge around what central atom, repel into what arrangement shape with what angles?

Bonding/non-bonding regions (how many), Shape?

2. Polar bonds, between which atoms, which is most electronegative?

3. Symmetrical? bond dipoles cancel or not

4. Dipole/no dipole, polar or non polar

How to explain molecular shape (LEBS)

Lewis diagram

Electron clouds - number of EC, bond angles and distribution (repel for max sep)

Bonding vs non-bonding regions (no. of each)

State final shape

What does melting point require

Requires the bonds between particles to be broken so that the particles can move out of position

Relate melting/boiling point to the strength of bonds/attractive forces + how much energy is required to break these bonds?

High melting/boiling point = strong bonds

Large amount of heat energy required to break strong bonds so particles can move out of position

Low melting/boiling point = weak bonds

Small amount of heat energy sufficient to break weak bonds so particles can move out of position

What does electrical conductivity require

A substance requires the presence of mobile and charged particles to conduct electricity. Electrons or ions must be present, and able to move.

How do ionic solids dissolve in water?

The positive end of the water molecules are attracted to the negative anions in the ionic solid, and the negative end of the water molecules are attracted to the positive cations.

The forces of attraction between the polar H2O molecules and the ions are strong enough to overcome the ionic bonds and pull the ions apart out of their 3D lattice structure.

How do molecular solids dissolve in solutes?

Like dissolves like - non-polar solutes will dissolve in non-polar solvents, polar solutes will dissolve in polar solvents.

The intermolecular forces of attraction that form between solute and solvent must be greater or similar in strength to the ImFoA between molecules WITHIN the solvent or solute to pull apart the solid and allow it to dissolve.

Steps to explain solubility

1. LEBS

2. Polarity - Polar bonds, between which atoms, which is most electronegative? Symmetrical? bond dipoles cancel or not, Dipole/no dipole, polar or non polar?

3. 'Like dissolves like'

4. Soluble/insoluble in whatever solvent

Steps for explaining properties

1. SPAB

2. Describe property's requirements

3. Explain how the substance meets/doesn't meet those requirements