Bridging The Gap Flashcards
When are ionic bonds formed
An ionic bond is the bond formed between positively charged and negatively charged ions (oppositely charged ions) due to the electrostatic forces of attraction between them.
When are covalent bonds formed
A covalent bond involves the electrostatic attraction between nuclei of two atoms and the bonding electrons of their outer shells
This occurs between two non-metals
Electrons are shared , not transferred
When are metallic bonds formed
A metallic bond is the electrostatic forces of attraction between delocalised electrons and positive ions.
Properties of ionic bonds
The properties of ionic bonding form into a giant ionic lattice which have a:
high melting/ boiling point due to the giant ionic lattices strong electrostatic forces of attraction
Soluble in polar solvent (water). This is due to polar molecules tend to overcome the electrostatic forces of attraction between ions within the giant ionic lattices by surrounding it when dissolved in water.
Poor conductivity in solid state. This is due to the ions being locked in place by the strong electrostatic forces of attraction. As a result cannot carry charge
High conductivity when the ionic solid is molten or dissolved in water as ions are able to move
Hard and brittle (all ions are locked in place)
Properties of simple molecular bonds
Low melting and boiling points- strong covalent bonds within the molecule although weak intermolecular forces - known to be very volatile
Gas at room temp due to weak intermolecular forces (low boiling point) thus changes state
Simple covalent molecules do not conduct electricity (no free ions to carry charge)
If the simple molecular structure are polar , they will dissolve in polar solvents but not in non-polar solvents. Additionally if they are non-polar they will dissolve in non-polar solvent but not polar solvents. (‘Like dissolves like’).
Properties of metallic bonds
Metals have high melting and boiling points. The strong electrostatic force of attraction is difficult to overcome and a large amount of energy is needed to break it, therefore a high temperature is required.
Metals can conduct electricity and heat. Metals are good conductors of both heat and electricity because they contain delocalised electrons which are free to move around and carry charge.
Metals are insoluble in all solvents except liquid metals. Metals cannot dissolve in solvents because metallic bonds are very strong (strong electrostatic forces of attraction)
Hard but are malleable and can be beaten into shape- and ductile - can be drawn into wires.
Formula for neutralisation reaction
Acid + base —> salt + water
Formula for metals with acids
acid + metal → salt + hydrogen.
Formula for alkali metal with water
Alkali metal + water —> alkali hydroxide + hydrogen
What is Endothermic (provide examples)
These are reactions that take in energy from the surroundings , thus making the surrounding colder.
Self freezing packs , electrolysis , reaction between ethanoic acid and sodium carbonate
What is exothermic ( provide examples)
Exothermic reactions are chemical reactions which release energy from the chemicals into the surroundings.
Combustion, self heating pads , glow sticks
How can you identify a endothermic reaction
If more heat energy was taken in when breaking the bonds than was released when making the bonds, the reaction is endothermic.
How can you identify an exothermic reaction
If more heat energy is released when making the bonds than was taken in when breaking bonds, the reaction is exothermic.
Properties of giant covalent structures
Very high melting points and boiling points as all the covalent bonds will need to be broken ; which require a lot of energy
They do not conduct electricity as they do not contain any charged particles (exception for graphite)
Insoluble in solvents as the solvent are unable to break the strong covalent bonds
