Chemistry - Level 1 NCEA properties

Melting and Boiling point of Ionic Substances

High due to strong attractive forces

solubility of ionic substances

Does not dissolve in non-polar solvents

Density of ionic substances

Strong ionic bonds so relatively dense

Electrical conductivity of ionic substances

Ions are fixed by directional ionic bonds. Cannot conduct electricity in a solid form only in liquid or aqueous states.

Thermal Conductivity in ionic substances

Good thermal conductivity as ions are packed closely together in 3D lattice

Malleability and brittleness of ionic substances

Not malleable because movement of ions is not possible, each ion bonded to many others in fixed positions in the solid.

Hardness and Softness

Hard strong directional ionic bonds hold ions in place in a regular lattice structure.

Melting and boiling points

MP energy required to break some attractive forces/bonds

BP energy required to break all bonds

Solubility

Ability of solvent particles to form bonds, with strong attractive forces, with solute particles

Density

Mass and how closely packed together particles are

Thermal conductivity

Ability to transfer thermal energy through vibrating particles.

Electrical conductivity

Mobile charged particles can carry a current

Malleability/brittleness

Ability to change shape without breaking

Hardness/Softness

Resistance to scratching/layers sliding over each other

Melting and boiling points in metals and alloys

Variable as it depends on how many delocalised electrons & charge on the ions. more valence electrons = stronger bonds

solubility of metals and alloys

Strong attractive forces mean that particles cannot form stronger attractions with solvents

Density in metals

Strong metallic bonds atoms are close together, high molar mass, most dense

Thermal conductivity in metals and alloys

Good thermal conductivity as delocalised electrons and metal ions are packed closely in a lattice.

Electrical conductivity in metals and alloys

Metal ions in a sea of delocalised electrons can conduct electricity as electrons can move in a sea of electrons

Malleability and brittleness of metals and alloys

metallic forces are between ions and electrons can change shape without breaking these bonds

Hardness and softness in metals

metals are hard as delocalised electrons prevent from repelling, however less hard than alloys because of strong metallic bonding and layers slide more easily

Density of alloys

Slightly less dense than metals due to differently sized particles

Hardness and softness of alloys

alloys are harder than metals as different sized atoms disrupt the layers sliding over each other

Melting and boiling points of simple

Weak attractive forces between molecules forces get stronger as molecules get bigger or heavier and stronger = increasing MP

Solubility of simple covalent networks

some polar molecules dissolve non polar molecules always dissolve

Density of simple covalent networks

weak intermolecular forces, cannot get too close together therefore cannot have high mass in a volume so density is low to medium

Thermal conductivity of simple covalent networks

low thermal conductivity (insulator) particles are not closely packed enough

Electrical conductivity in simple covalent networks

molecules with weak intermolecular forces cannot conduct electricity in any state as there are no mobile charged particles

malleability and brittleness of simple covalent substances

malleable, weak, non directional intermolecular forces hold molecules together

Hardness and Softness of simple covalent substance

weak, soft, non directional intermolecular forces hold molecules together

Melting and Boiling points of polymers

Moderate MP in long chain but is the same as simple (increasing MP)

Solubility of polymers

variable few dissolve and plastic solids don't generally dissolve

Density of polymers

weak intermolecular forces (stronger than simple) cannot get close so mass in a volume is low

Electrical conductivity in polymers

molecules with weak imf cannot conduct electricity in any state as there are no mobile charged particles

Thermal conductivity in polymers

low thermal conductivity

malleability or brittleness of polymers

depends. thermoplastic are malleable, thermosets are less malleable

Hardness or softness of polymers

Soft - medium depends on the chain branching

melting and boiling points in giant covalent networks

high due to attractive forces

solubility of giant covalent networks

do not dissolve in non polar molecules and some as metals

density in giant covalent networks

covalent bonds between atoms

thermal conductivity of giant covalent networks

variable, depends on structure

electrical conductivity of giant covalent networks

atoms with stronger directional covalent bonds 3D does not conduct 2D does not conduct as more delocalised electrons

malleability and brittleness of giant covalent networks

not malleable. covalent bonds are fixed in spaces atoms cannot move relative to each other

harness and softness of giant covalent networks

depends. 3D all have strong covalent bonds very hard 2D softer as layers can slide over each other so not very hard delocalised electrons.

Particles in ionic substances

made of cations and anions cation is usually a metal ion

attractive forces of ionic substances

an ionic bond is directional due to strong electrostatic forces of attraction between positive and negative ions

structure of ionic substances

ions are closely packed together in a 3D lattice by ionic bonding

particles of metals

made of metal atoms/cations and delocalised electrons

structure of metals

metal cations and delocalised electrons are closely packed together in a 3D lattice

attractive forces of metals

metallic bonds are the electrostatic attraction between metal cations and delocalised electrons. metallic bonds are non directional.

particles in an alloy

metallic substances are made of metal cations and delocalised electrons and another type of atom

structure of alloys

metal cations and delocalised electrons closely packed together in a 3D lattice

attractive forces of alloys

metallic bonds are electrostatic attraction between metal cations and delocalised electrons metallic bonds are non directional

particles in simple covalent networks

simple covalent substances are made of molecules of non metal atoms

structure of simple covalent networks

loosely packed together due to weak intermolecular forces of attraction

attractive forces of simple covalent networks

molecules are held together by weak intermolecular forces of attraction. these weak intermolecular forces get stronger as the molecules get closer together

particles of polymers

polymers are made of long chain molecules

structure of polymers

loosely packed together

attractive forces of polymers

weak intermolecular forces of attraction

particles of giant covalent networks

giant covalent networks are made of non metal atoms

attractive forces of giant covalent networks

atoms are held together by strong directional covalent bonds 3D is made of delocalised electrons 2D networks also have non directional weak attractive forces between the layers due to the delocalised electrons

structure of giant covalent networks

giant covalent networks exist as 2D and 3D lattices