Flashcards
GCSE Chemistry
Cards in this deck (123)
- 1What surrounds the nucleus of an atom?Electrons
- 2What is the charge of the nucleus?Positive (+1)
- 3What is the charge of an electron?Negative (-1)
- 4What is the overall charge of the atom?Neutral (0)
- 5What is the nucleus made up of?Protons and neutrons
- 6What are the relative masses of electrons, protons and neutrons?Electron: 0.0005 (negligible - 0)
Proton: 1
Neutron: 1 - 7Why are atoms neutral?Its subatomic particles have opposite charges and there is an equal number of both electrons and protons
- 8What is the approximate radius and mass of an atom?
- 9How are the element on the periodic table arranged?In order of increasing atomic number
- 10What are the horizontal rows on the periodic table?Periods
- 11What are the vertical columns on the periodic table?Groups
- 12What is the atomic number?The number of protons in an atom
- 13What is the mass number?The total number of protons and neutrons in an atom
- 14What are isotopes?Varieties of an element that have the same atomic number but different mass numbers.
- 15What determines whether a substance is an element or a compound given its formula?An element will only consist of one type of atom whereas a compound is a substance formed when two or more chemical elements are chemically bonded together.
- 16What can be used to work out the electronic structure of an atom?Its atomic number
- 17What is the maximum number of electrons in the inner shell?2 electrons
- 18What is the maximum number of electrons in the outer shell of the first 20 elements of the periodic table?8 electrons
- 19The atomic number of calcium is 20. What is its electronic structure?2 . 8 . 8 . 2
- 20Describe the main stages in the development of atomic structureDalton's atomic theory
J.J Thomson's discovery of the electron
Ernest Rutherford's nuclear atom
Bohr (electron orbits nucleus) - 21Describe Dalton's atomic theoryHe worked out some atomic weights, and invented symbols for atoms and molecules. He concluded that:
- all matter is made of atoms and they are indestructible
- all atoms of a particular element are identical to each other
- atoms are rearranged in a chemical reaction
- compounds are formed when two or more different kinds of atoms join together - 22How did the work of J.J Thomson, Rutherford and Bohr contribute to the development of the theory of atomic structure?The theory changed as new evidence was found.
Science explanations are provisional (existing for the present, possibly to be changed later) but more convincing when predictions are later confirmed. - 23Define 'ion'A charged atom or group of atoms as a result of atoms gaining or losing electrons, giving them either a positive or negative charge.
- 24What is the ion for chlorine which has lost two electrons? What is the ion for chlorine which has gained an electron?Cl ^ 2+
Cl - - 25What do atoms with an outer shell of 8 electrons have?A stable electronic structure
- 26How and why do metal atoms form positive ions?Metal atoms have 1, 2 or 3 electrons in their outer shell so when they form ions, they lose all of their electrons from their outer shell, giving them a positive overall charge.
- 27How and why do non-metal atoms form negative ions?Non-metals have 4 or more electrons in their outer shell so gain the correct number of electrons to complete this shell, giving them an overall negative charge.
- 28What happens in ionic bonding?A metal and non-metal combine by transferring electrons to form positive and negative ions which then attract one another.
- 29Ionic bonding of sodium chloride
- 30What is the electrical conductivity of sodium chloride like as a solid?Ionic compounds cannot conduct electricity when solid because the electrons in the ions cannot flow through to carry an electric current.
- 31What is the electrical conductivity of sodium chloride like as a molten liquid?The ions move apart and are able to move which allows the sodium chloride to conduct electricity.
- 32What is the electrical conductivity of sodium chloride like in solution?The ions are attracted to charges in water so are soluble in water. They separate when they dissolve so the solution conducts electricity.
- 33What are the melting points of sodium chloride and magnesium oxide?Sodium chloride - 800 degrees Celsius
Magnesium oxide - 2800 degrees Celsius - 34Why does magnesium oxide have a much higher melting point than sodium chloride?Because its Mg2+ and O2- ions have a greater number of charges, so they form stronger ionic bonds than the Na+ and Cl- ions in sodium chloride
- 35Describe the structure of sodium chloride or magnesium oxideA giant lattice in which positive ions are strongly attracted to negative ions
- 36What are some of the properties of substances that have a giant ionic lattice?High melting points (lot of energy needed to pull ions apart because of strong electrostatic attraction between positive and negative ions)
Conduct electricity in molten form or solution - 37Name the two types of bondingIonic
Covalent - 38What is ionic bonding between?Metals and non-metals
- 39What is covalent bonding between?Non-metals
- 40How do non-metals combine together and what type of bonding is this?Combine together by sharing electron pairs
Covalent bonding - 41Dot and cross model Covalent bonding of carbon dioxide
- 42Describe carbon dioxide and water in terms of their moleculesThey are simple molecules with weak intermolecular forces between molecules
- 43Give two physical properties of carbon dioxide and waterLow melting points
Do not conduct electricity - 44What do elements in the same group of the Periodic Table have?Similar chemical properties
- 45What is the group number the same as?The number of electrons in the outer shell
- 46The electronic structure for neon is 2 . 8. What group is neon in on the Periodic Table?Group 8
(8 electrons in the outer shell) - 47What do the periods on the Periodic Table correspond to?The number of occupied shells in the electronic structure
- 48Potassium is in period 4 on the Periodic Table. How many shells does it occupy in the electronic structure?4 shells
Electron structure: 2, 8, 8, 1 - 49Describe the main stages in the classification of elementsDobereiner - proposed 'law of triads', relative atomic mass of the middle element in a group of three elements was close to the average of the other two
Newlands - arranged known elements in order of atomic masses, proposed 'law of octaves' (every 8th element had similar properties)
Mendeleev - put known elements in order of relative atomic mass but left gaps for undiscovered elements and predicted what properties these might have - 50How did further evidence confirm Dmitri Mendeleev's ideas about the Periodic Table?Confirmation of his predictions about unknown elements.
Investigations on atomic structure (mass number and electronic structure) agreed with his ideas. - 51Why are the Group 1 elements known as the alkali metals?They form alkaline solutions when they react with water
- 52Why are Group 1 elements stored under oil?To prevent them reacting with oxygen and water vapour in the air
- 53How does the reactivity of the Group 1 elements vary?The reactivity with water increases as you go down Group 1 on the Periodic Table
- 54What forms wen lithium, sodium and potassium are reacted with water?Hydrogen and an alkali which is the hydroxide of the metal (e.g. sodium hydroxide)
- 55What happens differently when potassium is reacted with water (further down reactivity series)?Gives a lilac flame
- 56What is the word and symbol equations for the reaction between lithium and water?Lithium + water -> lithium hydroxide + hydrogen
2Li + 2H20 -> 2LiOH + H2 - 57Name the Group 1 elements in order from lowest reactivity to highestLithium
Sodium
Potassium
Rubidium
Caesium
Francium - 58Why do Group 1 elements have similar properties?Their atoms have the same number of electrons (1) in their outer shell so when reacted, they will each lose the one electron to form a positive ion.
- 59What is the balanced symbol equation for the formation of an ion of sodium?Na - e- --> Na+
- 60As we move down Group 1, why do the elements increase in reactivity with water?As you go down Group 1, the number of occupied shells increases as the elements are in different periods which means that the outermost electron gets further from the nucleus, making it more readily lost as the attraction is less.
- 61What is the loss of electrons called?Oxidation
- 62What are the flame test colours for lithium, sodium and potassium compounds?Lithium - red
Sodium - orange
Potassium - lilac - 63Describe how to use a flame test to identify the presence of lithium, sodium and potassium compounds1. Dip a clean flame test loop in the sample solution
2. Hold the flame test loop at the edge of a Bunsen burner flame
3. Observe the changed colour of the flame, and decide which metal it indicates
4. Clean the loop in acid and rinse with water, then repeat steps 1 to 3 with a new sample - 64What are the Group 7 elements known as?Halogens
- 65Name the five Group 7 elementsFluorine
Chlorine
Bromine
Iodine
Astatine - 66Give two uses of chlorineSterilise water
Make pesticides and plastics - 67Give a use of iodineSterilise wounds
- 68Describe the physical appearance of the Group 7 elements, chlorine, bromine and iodine, at room temperatureChlorine - green gas
Bromine - orange liquid
Iodine - grey solid - 69What do Group 7 elements react vigorously with?Group 1 elements
- 70What is the word equation for the reaction between sodium (Group 1) and chlorine(Group 7)?sodium + chlorine -> sodium chloride
(2Na + Cl -> 2NaCl) - 71What is the metal halide?The product of the reaction between Group 1 and Group 7 elements
- 72How does the reactivity vary in Group 7 elements?Decreases down the group
- 73What happens when Group 7 elements are reacted with metal halides?Displacement reaction takes place
- 74In the displacement reactions, what happens?A more reactive halogen displaces a less reactive halogen from a solution of its halide.
- 75What is the word equation for the reaction between chlorine and potassium bromide?Chlorine + potassium bromide -> potassium chloride + bromine
(Cl2 + 2KBr -> Br2 + 2KCl) - 76Why do Group 7 elements have similar properties?They all have seven electrons in their outer shell. An extra outer electron is gained during chemical reactions. An atom of a group 7 element will form an ion with a single negative charge
- 77Construct the equation showing the formation of a halide ion from a halogen moleculeCl2 + 2e- --> 2Cl-
- 78What is the gain of electrons called?Reduction
- 79Where are the transition elements positioned in the Periodic Table?Middle section
- 80What do all the transition metals have in common?They are metal and have metallic properties
- 81What are the colours of the transition metal compounds - copper, iron (II) and iron (III)?Copper - blue
Iron (II) - light green
Iron (III) - orange/brown - 82What are transition metals and their compounds often used as? Give two examplesCatalysts
Iron - Haber process
Nickel - manufacture of margarine - 83What is thermal decomposition?A reaction in which a substance is broken down into at least two other substances by heat
- 84What are the word and symbol equations for the thermal decomposition of copper carbonate?Copper carbonate -> copper oxide + carbon dioxide
CuCO3 -> CuO + CO2 - 85What two products are formed from the thermal decomposition of carbonates of transition elements (FeCO3, CuCO3, MnCO3, ZnCO3)?Metal oxide
Carbon dioxide - 86What is the balanced symbol equation for the thermal decomposition of iron carbonate?FeCO3 -> CO2 + FeO
- 87Define 'precipitation'A reaction between solution that makes an insoluble solid
- 88What can be used to identify the presence of transition metal ions in solution?Sodium hydroxide solution
- 89What type of precipitate is formed when the following ions are tested using sodium hydroxide solution? Cu2+ Fe2+ Fe3+Cu2+ gives a blue solid
Fe2+ gives a grey/green solid
Fe3+ gives a orange/brown solid - 90What are the solids formed in a precipitate reaction called?Precipitates
- 91What is the balanced symbol equation for the reaction between Fe2+ and OH- ?Fe2+ + 2OH- --> Fe(OH)2
- 92Why is iron used to make cars and bridges?It is hard and has tensile strength
- 93Define 'tensile strength'The resistance of a material to breaking under tension
- 94Why is copper used to make electrical wiring?It is a good conductor of electricity
- 95Give some properties of metalsLustrous, hard and high density
High tensile strength
High melting and boiling points
Good conductors of heat and electricity - 96How are particles in a metal held together?By metallic bonds
- 97Why do metals have high melting and boiling points?Strong metallic bonds
- 98How do metals conduct electricity?Metal atoms have outer electrons which are not tied to any one atom. These electrons can move freely within the structure of a metal when an electric current is applied.
- 99Describe metallic bondingThe strong attraction between a sea of delocalised electrons and close packed positive metal ions
- 100At low temperatures, what can some metals be?Superconductors
- 101Define 'superconductor'Material that conducts electricity with very little or no resistance at low temperatures
- 102Give three potential benefits of superconductorsLoss free power transmission
Super-fast electronic circuits
Powerful electromagnets - 103What is the main drawback of superconductors?Only work at very low temperatures which is not practical
- 104Name four types of water resources found in the UKLakes
Rivers
Reservoirs
Aquifers - 105Why is water an important resource for many important industrial chemical processes?It's a ...
cheap raw material
solvent
coolant to prevent overheating - 106Why is it important to conserve water?Water is essential to life and fresh, clean water is limited
For the protection of natural ecosystems
Saves energy (and money) - 107Name three pollutants that may be found in domestic water suppliesNitrate residues
Lead compounds
Pesticide residues - 108Why might drinking water contain nitrate residues?Nitrate fertilisers are very soluble in water and are easily washed off fields by the rain and then into rivers and reservoirs. Because nitrates are all soluble they cannot easily be removed from the water.
- 109Why might lead compounds be found in drinking water?Older houses and water supply systems still rely on lead pipes. Poisonous lead compounds formed on the inside of the pipes slowly dissolve into the water.
- 110Why might drinking water contain pesticides?Pesticides used by farmers to kill weeds or insects may be washed or blown into streams and rivers.
- 111Name some of the substances present in water before it is purifiedDissolved salts and minerals
Microbes
Pollutants
Insoluble materials - 112What does chlorination do?Kills microbes in the water
- 113What are the three stages of water purification?Filtration
Sedimentation
Chlorination - 114Why are some soluble substances not removed from water during purification?They are dissolved in the water so cannot be removed by the treatment processes.
- 115What are the disadvantages of using distillation of sea water to make large quantities of fresh water?Uses large amounts of energy
Needs specialised and expensive plant and equipment - 116What is used to test for sulfate ions?Barium chloride solution
- 117What happens when sulfate ions are present when tested using barium chloride solution?A white precipitate is formed
- 118What is used to test for halide ions?Silver nitrate solution
- 119When silver nitrate solution is used to test for halide ions, what do the following ions produce? Chloride ions Bromide ions Iodide ionsChloride ions - white precipitate
Bromide ions - cream precipitate
Iodide ions - yellow precipitate - 120What is the word equation for the reaction of barium chloride with sodium sulfate (sulfate)?barium chloride + sodium sulfate --> barium sulfate + sodium chloride
(BaCl2 + Na2SO4 --> BaSO4 + 2NaCl) - 121What is the word equation for the reaction of silver nitrate with sodium bromide (halide)?silver nitrate + sodium bromide --> silver bromide + sodium nitrate
(AgNO3 + NaBr --> AgBr + NaNO3) - 122Silver nitrate and barium chloride solutions are used for testing for the presence of sulfates and halides in what?Water
- 123What are the reactions of barium chloride with sulfates and silver nitrate with halides examples of?Precipitation reactions
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- GCSE Chemistry Flashcards on GCSE Chemistry, created by Zahraa Salman on 30/04/2017.
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