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79 Cards in this Set
- Front
- Back
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John Dalton |
All matter is made from atoms Atoms cannot be made or destroyed All atoms of a certain element are identical Different elements contain different types of atoms |
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J.J Thomson |
Atoms have subatomic particles called electrons. |
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Ernest Rutherford |
An atom is mostly empty space, with electrons arranged around a central nucleus. |
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Niels Bohr |
Electrons are arranged in shells or fixed orbits.
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Proton (Charge and Mass) |
+1 1 |
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Neuron (Charge and Mass |
0 1 |
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Electron (Charge and Mass) |
-1 0.0005 |
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Atomic Number |
The number of protons it contains (and electrons) The bottom number |
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Mass number |
The total number of protons and neutrons The top number |
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Isotopes |
A variety of an atom with the same atomic number but a different mass number |
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Element |
A substance with only one type of atom |
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Compound |
A substance with more than one type of element that can be chemically broken down |
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Electronic Structure |
2 electrons in the first shell 8 electrons in second and third shell |
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Ions (Definition, creation and formulae) |
Charged atom Created by the loss or gain of one or more negatively charged electron + or - to show if it's positively or negatively charged |
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Ionic Bonding |
Metal and a non-metal Usually the metal will lose an outer electron and the non metal will gain one The metal will become positively charged and the non metal will become negatively charged |
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Dot and Cross Diagrams |
electrons in the metal are dots electrons in the non metals or crosses
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Properties of Sodium Chloride |
High Melting Point Ionic Compound (needs lots of energy to break) Conduct electricity when molten or dissolved in water (Ions are free to move out of Giant Ionic Lattice) |
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Properties of magnesium Oxide |
High Melting Point Ionic Compound Does not dissolve in water Conduct electricity when molten |
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Giant Ionic Lattices |
Repeated many times, oppositely charged atoms attract to each other, forming ionic bonds |
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Formulae of ionic compounds |
Na+ + Cl- ----> NaCl Na+ + O2- ------> 2Na+ + O2- |
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Dobereiner |
Triads-elements with similar properties could be arranged into groups of three |
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Newlands |
Octaves-similar elements appeared in the same row and in relative atomic mass |
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Mendeleev |
Increasing atomic mass, left gaps for undiscovered elements and predicted their properties. |
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Filling in The Gaps |
eka-aluminium was discovered as gallium
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Iodine and Tellurium |
Iodine should have gone first as it has a lower RAM but he swapped it so Iodine was in group 7 with chlorine and bromine. Iodine was later discovered to a greater Atomic Number then Tellurium so Mendeleev was correct even if he was unaware of it at the time |
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Groups and Periods |
Horizontal rows are periods Vertical Columns are groups |
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Electronic Structure and the Periodic Table |
The amount of electrons in the outer shell of an electron determines the group it belongs to on the periodic table |
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Covalent Bonding |
A non-metal and a non-metal |
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Molecule |
A particle containing two or more atoms chemically bonded together Different to a compound because it can have atoms of the same element |
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Properties of Carbon Dioxide |
low melting point weak intermolecular forces between molecules if carbon and oxygen Gas at room temperature Don't conduct electricity (no overall electrical charge)
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Properties of Water |
Low melting point Liquid at room temperature weak intermolecular forces between hydrogen and oxygen molecules Don't conduct electricity (no overall electrical charge) |
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Dot and Cross diagrams in Covalent Bonding |
Only the outer shell electrons are shown Shared electrons are shown in a cross over area |
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Group 1 Elements |
All metals React with water to create alkaline solutions Called the Alkaline Metals Reactivity with water increases as you go down the group |
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Lithium, Sodium and Potassium |
Stored under oil because they are too reactive with air and water. |
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Reactions with Water |
Sodium + Water -------> Sodium Hydroxide + Hydrogen Lithium + Water -------> Lithium Hydroxide + Hydrogen Potassium + Water -------> Potassium Hydroxide + Hydrogen |
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Lithium in water |
Disappears slowly Keeps its shape Doesn't ignite in water |
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Sodium |
Disappears quickly Forms a silver ball Doesn't ignite in water |
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Potassium |
Disappears very quickly Forms a silvery ball Ignites in water with a lilac flame |
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General Equation for the Reaction of Group 1 Elements and Water |
2M + 2H2O ------> 2MOH + H2 |
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Trends in Alkaline Metals |
The easier it is for a group 1 element to lose an electron, the more reactive it is When an electron has a low level of attraction the the nucleus, it is easier for it to lose that electron |
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Oxidation General Reaction |
M ------> M+ + e- |
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Flame Test Results (Lithium, Sodium and Potassium) |
Lithium=Red Sodium=Orange Potassium=Lilac |
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Flame Test Method |
-A loop of nichrome alloy wire is attached to a metal handle and cleaned in acid -Dipped in solid sample and placed in bunsen burner flame to test for colour |
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Group 7 Elements |
Halogens (salt formers) React with metals to make salts Reduce in reactivity as you go down the group Gain an electron to become a negative ion when they react |
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Uses of Chlorine |
Sterilises tap and swimming pool water In the making of PVC Plastics and pesticides and polyvinyl chloride
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Uses of Iodine |
Antiseptic in sterilising wounds |
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Colours of Halogens at Room Temperature |
Chlorine is a green gas Iodine is a grey solid (warmed easily to a purple vapour) Bromine is an orange liquid |
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Reactions with Metals |
React vigorously with alkaline metals Sodium + Bromine ------> Sodium Bromide |
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General Equation for the Reaction of a Group 1 (M) Element and a Group 7 (X2) Element |
2M + X2 ------> 2MX |
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Displacement Reactions |
Group 7 elements can react with Metal Halides (Group 1 element + Group 7 element) |
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Displacement Reaction Example |
Chlorine + Sodium Bromide ----------> Bromine + Sodium Chloride |
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Displacements Order in Group 7 Metal Halides |
Fluorine displaces Chlorine Chlorine displaces Bromine Bromine displaces Iodine Iodine displaces Astatine |
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General Equation for Group 7 Displacement Reactions |
X2 + 2MY ------> Y2 + 2MX |
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Reduction Reaction General Equation |
X2 + 2e- -----> 2X- |
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Transition Metals Properties |
Malleable Shiny when cut Hard Compounds often used as catalysts |
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Coloured Compounds |
Copper compounds are often blue Iron (II) compounds are often light green Iron (III) compounds are often orange-brown |
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Thermal Decomposition Reaction |
One substance breaks down to form two or more other substance when heated.
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General Equation for a Decomposition Reaciton |
Metal Carbonate + Heat ------------> Metal oxide + Carbonate dioxide |
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Carbon Dioxide Test |
Limewater turns milky in the presence of carbon dioxide |
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Precipitation Reactions |
Two or more solutions react to make an insoluble solid The solid is called the precipitate and makes the mixture cloudy |
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Hydroxide Precipitates |
When a compound of transition metals dissolve in water, the positively charged metal ions spread out and react with the negatively charged hydroxide ions in water to form coloured hydroxide precipitates. |
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Colours of Created Hydroxide Precipitates |
Copper(II) -----Cu2+ ----- Blue Iron (II) ----- Fe2+ ---- Grey-Green Iron (III) ---- Fe3+ ----- Orange-Brown |
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Symbol Equationfor Copper (II) Ions and Hydroxide Ions |
Cu2+ + 2OH- ----- Cu(OH)2 |
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Copper and Iron Uses |
Copper is a good conductor of electricity. Used to make brass and electrical wiring. Iron is used to make steel for cars and bridges.
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Metal Properties |
Hard Shiny and Lustrous Good Conductors of Heat and Electricity High Tensile Strength (Can't be stretched) High Melting and Boiling Points
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Metals and Ions |
Metals have lots of positive metal ions created by the loss of electrons in each atom. The free electrons form a "Sea" of delocolised electrons. Metallic bonding is the force between the delocolised electrons and the metal ions. The force is strong, giving them high melting and boiling point.
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Metal Crystals |
Contain delocalised electrons Particles in solid metals are arranged so that they are packed closely and repeated many times. The repetiiton produces crystals |
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Electrical Resistance |
When the delocalised electrons cross paths with the poistive metal ions, electrical resistance happens. Resistance creates waste heat energy |
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Superconductors |
Materials that have little or no resistance to the flow of electricity Metals at low temperatures sometimes become superconductors |
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Superconductors Uses |
Powerful Electromagnets MRI Scanners
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Superconductors could be used for.... |
Super fast electronic circuits Quicker carrying of electricity in metal cables to homes, factories and offices. Co |
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Cons of Superconductors |
Only work at very low temperatures (below -200 degrees Celsius)
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Water Sources |
Reservoirs Lakes Underground Reservoirs 97% of the Earth's water is salt water, so fresh water needs to be preserved |
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Water uses |
A solvent A coolant A cheap raw material |
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Pollutants in Water |
Nitrates from fertilisers Lead compounds from old led pipes Pesticides from crops sprayed in it |
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Purifying Water |
Sedimentation-Removes large suspended particles (sand and soil (etc) settle at the bottom after time) Filtration-Removes smaller suspended particles Chlorination-Kills microbes (prevents disease)
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Distillation |
Creates very pure water from sea water. Needs a lot of energy though, it's expensive. |
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Testing for Sulfate Ions |
Barium chloride is added to water and if it creates a white precipitate of barium sulfate then sulfate ions are present Sodium Sulfate + Barium Chloride ----> Sodium Chloride + Barium Sulfate Na2SO4 + BaCl2 ---> 2NaCl2 + BaSO4 |
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Testing for Dissolved Halide Ions with Silver Nitrate |
Chloride ions = A white precipitate NaCl2 + AgNO3 ----> NaNO3 + AgCl Bromide ions = A cream precipitate Iodide ions = A pale yellow precipitate |
