C4 revision cards GCSE
- Created by: Beth
- Created on: 12-06-13 09:56
C4 REVISION CARDS
Atoms :
- atomic structure includes a nucleus (which is made up of protons and neutrons) surrounded by electrons that go round on the orbitals.
- electrons = negative charge and mass of 0.0005, protons = positive charge and mass of 1, neutrons = no charge and mass of 1.
- atomic number = number of protons/electrons
- mass number = number of protons + number of neutrons
- isotopes are varieties of the same element --> they have the same atomic number but different mass numbers
C4 REVISION CARDS
More on Atoms:
- atoms with an outer shell of 8 electrons have a stable electronic structure
- metal atoms form positive ions, non-metal atoms for negative ions
- ionic bonding, a metal and non-metal combine by transferring electrons to form positive ions and negative ions which then attract one another.
- the structure of sodium chloride and magnesium oxide is a giant ionic lattice in which positive ions are strongly attracted to negative ions
- sodium chloride has a high melting point and can conduct electricity when molten or in solution.
C4 REVISION CARDS
Covalent Bonding:
- covalent bonding is between metals and non-metals, and it involves the sharing of electrons
- carbon dioxide and water are simple molecules with weak intermolecular forces between molecules
- the group number of an element is the same as the number of electrons in the outer shell
- the period in which the element belongs to corresponds to the number of occupied shells in the electronic structure
- carbon dioxide and water: have the following properties: low melting points and they do not conduct electricity
C4 REVISION CARDS
Group 1:
- group 1 metals are also known as alkalie metals because they form alkaline solutions when reacting with metal. They also react vigorously with water to form hydrogen and hydroxide e.g. 2Na+2H2O-->2NaOH+H2
- group 1 metals have similar properties, in terms of forming positive ions (1+) with stable electronic structures.
- when group 1 metals react with water they lose an electron e.g. Li --> Li+ e- This loss of an electron is oxidation. The reactivity of group 1 metals increased down the group.
THE FLAME TEST can be used to identify metals:
1) use of moistened flame test wire, then dip the flame test wire into a solid sample.
2) the flame test wire is then put into blue bunsen flame, and the colour of the flame is recorded
- Lithium = red, Sodium = orange, Potassium = lilac
C4 REVISION CARDS
Group 7:
- chlorine = green gas, bromine = orange liquid, iodine = grey solid
- group 7 elements are known as halogens, and halogens react with group 1 metals to form halides
- halogens get LESS reactive down the group
- they can react in displacemnt reactions, the most reactive elements ends up in the compound and "kicks" the least reactive element out e.g. - chlorine displaces bromides which displaces iodides e.g. CL2 + 2KBr --> 2KCL + Br2
- group 7 elements all have similar properties as they all have 7 electrons on their outer shell
- when halogens react, they gain an electron, this is reduction
C4 REVISION CARDS
Compounds:
- compounds of a transitions element are often coloured; copper compounds are often blue, iron(II) compounds are often light green and iron(III) are often orange/brown.
- transitions elements and their compounds are often used as catalysts; iron in the Haber process, nickle in the manufacture of margarine
- transitions metal carbonates decompose to give a metal oxide and carbon dioxide - this results in colour change.
- sodium hydroxide solution is used to identify the presence of transition metal ions in solution.
- Cu2 gives a blue solid - Fe2+ gives a grey/green solid - Fe3+ gives an orange/brown solid )- all of these solids are called precipitates e.g. Cu2+ + 2OH- --> Cu(OH)2
C4 REVISION CARDS
Metallic Bonding and Superconductors :
- metals have high boiling points due to strong metallic bonding.
- metallic bonding is a strong electrostatic force of attraction between positively charged metal ions and a "sea" of delocalised electrons; these delocalised electrons allow metals to conduct electricity.
- metallic bonding means to have high melting and boiling points
- superconductors are materials that can conduct electricity with little or no resistance . They form at low temperatures, and the temperature that a superconductor forms is called the critical temperature. Superconductors have no magnetic field.
- potential benefits of superconductors: - loss free power transmission - super fast electronic circuits - powerful electromagnets
C4 REVISION CARDS
Water Purification:
- 3 stages to water purification: 1) sedmentation 2) filtration using sand 3) chlorination
- lead pipes lead to lead being in the water; nitrates enter the water system from fertiliser run off; pesticides enter the water system from pesticides spraying near water courses.
- sea water is not used as drinking water as it would be too expensive to purify it
- to test for the presence of sulphate ions, add barium chloride - a positive result will show a white precipitate// barium chloride + magnesium sulphate --> barium sulphate (white ppt) + magnesium chloride --- BaCl2 (aq) + MgSO4 (aq) --> BaSO4 (a) + MgCl2 (aq)
- to test for the presence of halidides, add silver nitrate: chloride = white precipitate, bromide = cream precipitate, iodide = yellow precipitate // silver nitrate + sodium chloride --> silver chloride (white ppt) + sodium nitrate --- NaCl (aq) + AgNO3 (aq) --> AgCl (a) + NaNO3 (aq)
Related discussions on The Student Room
- Help for Pschology gcse »
- GCSE »
- Mobile phones should be banned from the classroom? »
- flashcards or memorising flashcards during y10 summer? »
- is using only freesciencelssons good for gcse revision »
- Should I start revising »
- GCSE revision »
- GCSE revision year next year »
- is this good way of revising for gsces? »
- Using flashcards - GCSE revision »
Comments
No comments have yet been made