Types of Solids

PURE substances

Substances that have different structures depending on their type of bonding.

Copper

Metallic solid

sodium chloride (salt)

Ionic solid

diamond and graphite

covalent network solids

carbon dioxide and water

simple molecular solids

Crystalline solids

if they have a regular repeating pattern

Amorphous solids

When the arrangement is not orderly or does not have a long-range repeating pattern. Happens when the liquid solidifies before the atoms have been arranged in a structure

what are metallic solids made up of

atoms

3D lattice

Atoms closely packed together

Delocalised electrons

The atoms lose their valence electrons, they then do not belong to any particular atomand can move freely throughout the metallic solid,

Cations

atoms that are now positively charged because they have lost electrons

Metallic bond

Electrostatic attraction between positive ions and electrons

most metals have high melting and boiling points

because the metallic bond is very strong so it requires a lot of energy to break.

metal atoms are typically arranged in layers

the layers can slide over each other without disrupting the bonding therefore metals are ammeable and ductile

non directional bonds

attraction between ions and electrons are not limited to a specific direction.

mobility of delocalised electrons

allow metals to conduct electricity and disperse heat energy

what are ionic solide made of

ions

cations

positive

anion

negative

ionic bond

force of attraction between positive and negative ions

Simple molecules in ionic solids

do not exist

DIAMOND

Has a structure where every C atom is joined to 4 others by strong bonds.

SILICA (Silicon dioxide SiO2)

has a similar structure to diamond where every Si atom is joined to 4 O atoms.

how do ions attract each other

electrostaticlly

mass of sample and ratio of ions

different samples will have different numebrs of ions but the ratio will not change

what form are most ionic substances at room temp

solid

most ionic solids have high melting and boiling points

because a lot of energy is needed to break the bonds

why are ionic solids brittle although tehy are hard

When a force is applied to the solid, the structure is disrupted

since similarly charged ions are positioned next to each other.

The ions repel each other and the lattice structure breaks apart.

Electrical Conductivity of Graphite

FREE ELECTRONS between the layers mean that graphite CONDUCTS ELECTRICITY

PHYSICAL PROPERTIES are deternimed by

the structure of a substance

when can ionic compounds conduct electricity

when ions can move freely, so in a liquid state or when dissolved in water. The can not in an ionic solid

What are molecular solids made up of

molecules

intramolecular forces

between atoms in each molecule. very strong

Intermolecular forces

between molecules, weak, determine the properties of a molecular solid

what does increasing molecular mass do

number and overall strength of intermolecular forces increases, so melting and boiling points increase

why do simple molecular substances have low melting and boiling points,

bc the intermolecular forces are very weak

can molecular solids conduct electricity

As the molecules are NOT CHARGED simple molecular substances

DO NOT CONDUCT ELECTRICITY when solids, liquids or gases.

SOLUBILITY in water

yes, if polar

like dissolves like

also true for non-polar substances

GIANT MOLECULAR SUBSTANCES or COVALENT NETWORKS

strong covalent bonds join atoms together with other atoms of the same type to make giant structures, rather than little groups.

why do covalent networks usually Have HIGH melting / boiling points and are usually HARD and STRONG

joind by very stong bonds