AoS1 - Ionic Compounds and Metals Flashcards
What is an Ionic Compound?
A compound made up of cations and anions in which produce a neutral substance.
- Metal transfers valence electrons to the Non-metal.
Electrostatic Forces in Ionic Bonding
The forces between the anion and cation that hold the compound together, creating ionic bonding.
Neutral Substance
The Ion charges cancel out
Arrangement of Ionic compounds
Crystal lattice structure
- Ions are in fixed positions in a lattice.
- based on size and ratio of the ions
How are ions held together in Ionic Bonding?
The attraction between the anions and cations. This is called the ionic bond.
The most stable arrangement of ions in Ionic Bonding
Positively charged ions are packed to the nucleus as closely as possible to the negatively charged particles. Ions with the same charge are as far away as possible.
Co-ordination number
Used to describe the ratio of ions.
Properties of Ionic Compounds
- High melting and
boiling points - hard
- brittle
- conductivity
- solubility
Explain the high melting and boiling point of Ionic Compounds.
Attractive forces between the ions are strong and therefore a large amount of energy is required to break these bonds.
Explain the hard but brittle property of Ionic Compounds.
Forces between ions are strong, hence it is very hard to break these forces. However, when these forces are broken and the lattice structure shifts and repulsions occur between like charges, structure is shattered.
Conductivity of Solid Ionic Compounds.
Do not conduct electricity as there is no free moving ions
What is a molten compound?
Are compounds that are heated into a liquid
Conductivity of Molten and Aqueous Compounds in Ionic Bonding
There are free moving ions that can therefore conduct electricity
Solubility of Ionic Compounds
Solubility varies depending on the ionic bond strength. Compounds that form really strong bonds will be insoluble in solution
Monoatomic Ion
Are ions containing one atom only
Polyatomic Ion
Are ions made up of more than one atom
If an ion forms more than one ion
Must specify the charge when naming
Transition metals (in terms of forming ions)
- Tend to loose electrons to form cations
- some elements will form more than one stable ion
Why can transition metals form more than one ion?
- similar energy levels in 3d and 4s orbitals
- valence electrons can easily jump to both
Naming anions
Suffix “ide” is added + ion
Empirical Formula
The simplest whole number ratio of atoms in a compound
Chemical Formulae Rules
- When naming and writing ionic compounds, cations written first
- Positive and negative charges must be balanced
- Subscripts indicate number of ions
- Electrovalency must be specified
Solubility Rules
Can be used to predict whether an ionic compound will be soluble or insoluble under standard Laboratory Conditions
Standard Laboratory Conditions
25 degrees and 1 atmosphere pressure
Determining Solubility
Identify anion and determine if soluble then identify if cation is soluble or an insoluble exception.
Precipitation reaction
A reaction in which a precipitate is formed
Precipitate
An insoluble solid that forms when two or more solutions are mixed. Solid seperates from the solution.
Why does a solid form in a precipitate reaction?
The attraction between cations and anions is greater than the attraction between the individual ions and the surrounding water molecules.
Balanced formula Equation
Shows all reactants and products (including spectator ions)
Spectator Ions
Ions which remain in solution and are unchanged (not involved).
Ionic Equation
Only shows reacting species which produce the precipitate.
What percent of atoms in the earths crust are metals?
25%
Metals exist in
Element form or as compounds
Element form
very unreactive eg. Gold and Silver
Compound form
combined with non-metal elements called ores
Properties of Metal compounds
- Strong
- Can be light
- Ductile
- Conducts Electricity
- Malleable
- Lustrous
Metallic bonding model
Arranged in a metal lattice.
Lattices differ in charge on the metal ion and the size of the metal ion.
What is a lattice?
3-d regular arrangement of particles
Positive Ions in Metal Lattice
Form regular 3d lattice, fixed positions and closely packed.
Valence Electrons in Metal Lattice
Free to move, delocalised electrons that belong to the lattice as a whole, sea of electrons
Electrons in Inner shells of the Metal Lattice
Localised
Attraction in metal compound
Attraction between positive cations and delocalized electrons creates metallic bonds.
Conductivity of Electricity - Metal
Contains charged particles that are free to move (delocalised electrons)
If a current is applied, the electrons are forced in at one end and an equal number flow out the other, hence producing a current.
Conductivity of Heat - Metal
When delocalised electrons bump into each other and the positive ions, they transfer electricity