Year 9 Term 2 Flashcards
Metal atoms lose electrons during reactions and will always…
Form positive ions
Non-metal atoms gain electrons and always…
Form negative ions
Group one elements form
1+ ions
Group 2 elements form
2+ ions
Group 6 elements form
2- ions
Group 7 elements form
1- ions
Do compounds have a charge
No because charges must cancel out when working out the overall formula
What do ionic compounds contain
Metals and non-metals
What does dissolve mean
When some solids are out into a liquid like water, they appear to get smaller, some solids seem to disappear. This is called dissolving
Decanting
Insoluble solid from liquid
Filtration
Insoluble solid from liquid
Evaporation
Solute from a solution
Distillation
Solvent from a solution
Fractional distillation
Mixture is miscible liquids
Separating funnel
Mixture of miscible liquids
Chromatography
Mixture of miscible liquids
Soluble solute + solvent —>
Solution
Insoluble solute + solvent —>
Solute + solvent
What is chromatography
Separating the different inks in a pen. Each colour travels different distances. All inks in pen are water soluble and travel up chromatography paper. The greater the distance travelled, the more soluble it is
Why do elements react
Because they want a full outer shell
How do elements react
By gaining or losing an electron(s) from/to the outer shell
Why are Nobel gases unreactive
Because they have a full outer shell so don’t need to gain/lose and electron
Ionic bonding
Metals and non-metals
Outer electrons become delocalised
Produces positive ions and delocalised electrons
Giant covalent bonds
Non-metals
Share electrons
Particles = atoms
Covalent simple molecular bonding
Non-metals
Share electrons
Particles= molecules
How are ions held together
They are held together by strong forces of attraction between oppositely charged ions. The electrostatic force of attraction is called the ionic bond
Why are ions in a giant structure held together so strongly
The force exerted by an ion on the other ions acts equally in all directions
Why are metals always positively charged
Because they lose an electron
Why are non-metals always negatively charged
Because they gain an electron
Does solid sodium chloride conduct electricity?
No because it needs to be able to move freely (liquid) and solid can’t.
Does sodium chloride dissolved in distilled water conduct electricity
Yes because it can move freely and contains ions. Because they can move and carry a charge
Can distilled water conduct electricity
No because it doesn’t contain ions so doesn’t conduct
Does molten sodium chloride conduct electricity
Yes because it can move freely and contains ions so can carry a charge
To conduct electricity particles need to…
Be able to move freely and particles need to have a charge
Ionic compounds conduct electricity when molten or dissolved in water because…
They can move freely because it’s a liquid and can conduct electricity because it’s an ionic compound. Charged particles can carry a charge
Ionic compounds do not conduct when solid because
They are solid so vibrate about a fixed point so the ions cannot move to terminals
Ionic compounds have high melting and boiling points because
There is a strong force of attraction between ionic bonds so a lot of energy is needed to break attraction
What is a covalent bond
A shared pair of electrons
How to draw a covalent bond
Only draw the outer shell
Cl-Cl the line represent the covalent bond between the atoms
Can covalent compounds conduct electricity
No because they don’t have an overall charge
Do simple molecular substances conduct electricity
No because they aren’t electrically charged, they are neutral
Why do simple molecular substances have a low melting and boiling point
Because there are weak forces between the molecules
Why do covalent substances not conduct electricity
Because the molecules don’t have an overall charge - don’t contain free ions or electrons
Why do diamond and graphite have a high melting and boiling point
Because there are many strong covalent bonds to break
Why is diamond hard and why is graphite soft
Diamond is hard because the atoms are held together by many strong covalent bonds
Graphite is soft because the layers of atoms can slide
Why can’t diamond conduct electricity and why can graphite conduct electricity
Diamond can’t because there are no free electrons/ ions
Graphite can because it has an outer delocalised electron
What does delocalised mean
Free to move if there is a delocalised electron, it can conduct electricity
Buckminster fullerene
Arranged in pentagons, hexagons and spheres
