Bondings Flashcards
When does ionic bonding happen and how ?
With metal + non-metal
When atoms lose or gain electrons
What does ionic bonding form
Giant ionic lattice by strong electrostatic forces of attraction
What are the properties of ionic bonding
- Cannot conduct electricity when solid as ions are fixed and connot move but when dissolved in water it can
- Soluble
- Extremely high melting and boiling points due to strong attraction between ions
Why can’t ionic compunds conduct electricity when solid
Ions cannot move they are locked together by strong electostatic forces of attraction
And in water they are free to move
Properties of metallic bonding
- Do conduct electricity
- high melting point as electrons are very strong
- insoluble in water
- carry electrical currents and thermal energy
- electrostatic attractions hold everything together
- Sea of delocalised electrons
*shiny
Metallic bonding
The electrons of the outer shell of the metal atom are delocalised (free to move around). There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons.
What is covalent bonding?
A covalent bond is a strong bond that forms when a pair of electrons is shared between two atoms
Giant covalent
In giant covalent structures, all the atoms are bonded to each other by strong covalent bonds.
Properties of giant covalent
Examples
- Very high melting and boiling points as lots of energy is needed to break bonds
- don’t conduct electricity as they don’t contain charged particles apart from graphite or graphene
- Every atom is connected bt strong covalent bonds
- They are always solid at room temperature
- They aren’t soluable in water
Diamond, Graphite and silicon dioxide
Simple covalent bonds
They have a small and fixed number of atoms
Examples of simple covalent bonds
Hydrogen
Hydrogen chloride
Water
Oxygen
Methane (co2+H)
Carbon dioxide
Properties of small covalent bonds
- Low melting and boiling points because molecules are easily parted from each other
- Usually gases or liquids at romm temperature
- They all boil below room temperature
- Does not conduct electricity because the molecules do not have any free electrons and an overall electric charge
- Strong covalent bonds but weak intermolecular forces so not engough energy to keep bonds togather when boiling so not much energy is needed for covalent molecules to go from liquid to gas
- If the molecule gets bigger so does the the strength of the inter molecular forces so more energy needed
Intermolecular
Forces of attraction between molecules
Weak intermolecular forces
The weak intermolecular forces between the molecules do not require a lot of energy to break
Diamond
Explain properties and bonding
-Diamond is made up by a network of carbon atoms that each form 4 covalent bonds
-Diamonds have high melting points because they have strong covalent bonds so it takes a lot of energy to break them
-They can’t conduct electricity as they have 4 bond so no extra electron to carry charges
-Rigid lattice structure making it really hard
-Can use to strengthen cutting tool
How are polymers made?
Polymers are molecules made up of long chains of covalently bonded carbon atoms
They are formed when lots of small molecules called monomers join together
Properties of polymers
Most polymers are solid at room temperatures and have a high melting point
Forces of attraction between polymers
The intermolecular forces of attraction happen between polymers molecules are relatively strong so it takes a lot of energy to break these forces
Metallic bonding
Metalic bonding happens between 2 metals, they have a strong electrostatic forces attraction between the delocalised negative electrons and the positive metal ions
Its structure is a sea of delocalised electrons making a lattice
Metalic bonding is very strong
Properties of metals
Have metalic bonding so needs lots of enerfy to be broken
Malleable layers of atoms in pure metal can slide over each other
Good conductors of electricity as delocalised electrons carry electrical charge and thermal energy
High melting and boiling points so shiny at room temperature
Sonorous
What’s an alloy ?
An alloy is a mixture of metals
Graphite
Properties
-Each carbon atoms only forms 3 covalent bonds creating hexagons
there’s no covalent bonds between layers so weakly bonded therefor they are free to move over each other
-High melting point
-Only three out of 4 outer electrons are used in bonds so each carbon atom has one electron that is delocalised and free to move, so conducts electricity
-Soft and slippery so its ideal as a lubricating material
How are ionic bonds formed ?
When a metal transfers one or more electrons to a non-metal atom to form two oppositely charged ions and then theses two ions will then be attracted to each other by electrostatic forces forming an ionic bond
Why do the charges on ions cancel out?
In an ionic compounds, the charges on the ion have to cancel out to leave a overall charge of zero
What does ide mean
Ionic compounds that are monotomic ions (by itself) - sulfide s2-
What does ate mean
Ionic compounds made from 3 or more different elements end in -ate
They contain more oxygen
Sulfate s04 ( 2-)
What does ite mean
mean that it contains oxygen - less oxygen
Sulfite - s03 (2-)
What is graphene?
A single layer of graphite
It is one atom thick making it a two dimentional substance
Its a sheet of carbon atoms joined together in hexagons
A type of fullerene
Properties of graphene
An excellent conductor of electricity because it has delocalised electrons which are free to move around
What is fullerene?
Properties
Fullerenes are molecules of cabon atoms with hollow shapes (balls)
They usually have a hexagonal rings of carbon atoms but they can also have 5 or 7 rings
They can be used to cage other molecules. The fullerene structure forms around other atoms or molecule which is then trapped inside,
What can fullerene be used for
Pharmaceutical delivery, lubricants and catalysts
Carbon nanotubes have high tensile strength (can be streched) and good conductors of electricity
