Structure And Bonding Flashcards
Ionic bond
The strong electrostatic attraction between oppositely charged ions
When does ionic bonding occur
Between metals and non metals
Why do ionic compounds have high melting and boiling points
The strong electrostatic attraction between oppositely charged ions require a lot of energy to break
When can ionic compounds conduct electricity
When molten or in solution
Why can’t ionic compounds conduct electricity when solid
The IONS are fixed in position and not free to move around
Why can ionic compounds conduct electricity when molten or in solution
The IONS are free to move around
Ionic compounds structure
Giant ionic lattice structure
Covalent bond
The electrostatic attraction between two positive nuclei and a shared pair of electrons
Compound
A substance formed from two or more elements, chemically combined
Simple covalent structure
Covalent molecules that contain only a few atoms
Simple covalent structure bonding
Week forces of attraction between molecules and are easy to overcome
Properties of simple molecular structures
Fixed amount, Low melting and boiling points, weak forces of attraction, brittle, can’t conduct electricity,
Why can’t simple molecular structures conduct electricity
There are no mobile electrons or ions to carry a charge
Why is diamond hard
Each carbon atom forms four bonds to other carbon atoms in a giant tetrahedral lattice structure
Why is graphite soft and slippery
There are weak forces of attraction between the layers so they can slide over each
Why can graphite conduct electricity
It has mobile electrons that are free to move through the structure
Why can’t diamond conduct electricity
There are no delocalised electrons that are free to move
C60 structure
Simple molecular structure
C60 bonding
Strong covalent bonds and weak intermolecular forces of attraction
C60 energy
Little energy is needed to overcome the weak intermolecular forces
Why can’t C60 conduct electricity
Delocalised electrons can move within a molecule, but can’t jump from molecule to molecule
Why is C60 slippery
Weak intermolecular forces of attraction between the layers
Metallic bonding
Strong electrostatic attraction between layers of positive metal ions and the sea of mobile delocalised electrons
General properties of most metals
Conduct electricity, malleable, high melting and boiling points
Why do metals conduct electricity
The delocalised electrons are mobile
Why are metals malleable
The layers of metal ions are able to slide over each other because of the weak forces of attraction between them
why do simple molecular substances have low melting and boiling points
the intermolecular forces are very weak so don’t require a lot of energy to overcome
what are simple molecular substances at room temperature
liquid, gas or an easily melted solid
in simple molecular substances, why are the intermolecular forces stronger between molecules with a high relative molecular mass
there are more points along the larger molecules for intermolecular forces to act between them, so more energy is needed to break the forces.
why do molecules with a high relative molecular mass have
higher melting and boiling points because of the strong intermolecular forces that require lots of energy to break
why do giant covalent lattice structures have high melting and boiling points
The strong covalent bonds require lots of energy to BREAK
Metal structure
Giant metallic lattice of positive ions and a sea of delocalised electrons
Malleable
Can be hammered into different shapes and positions
Diamond and graphite structure
Giant covalent lattice structure
Metallic bonding between
Metal and metal
Ductile
Can be drawn into a wire
do covalent compounds conduct electricity
no
covalent bonding between
non metal and non metal
When do you have a simple molecular substance
Atoms that are joined by covalent bonds that make a molecule. The substances are made up of the molecules
