Flashcards
Atomic Structure. AQA Chapter 1
Flashcards do conjunto (25)
- 1AtomsAll substances are made up of tiny particles called atoms. There are about 100 different types of atoms on Earth. These can combine in a huge variety of ways, giving all those different substances.
- 2Periodic TableThe periodic table lists a;; the chemical elements, with eight main groups each containing elements with similar chemical properties.
- 3ElementsA relatively small number of substances that are made up of only one type of atom are known as elements. An atom is the smallest part of an element that can exist. There are only about 100 different atoms so only 100 different elements. Elements can have different properties can be metal or non-metal and can be at different states of matter at room temperature.
- 4CompoundsMore than one type of atom bonded together. Chemical bonds hold the atoms tightly in compounds. Some compounds are made from two types of atom however most compounds consist of more than two different types of atom.
- 5What happens to atoms in a chemical reactionNo new atoms are ever created or destroyed in a chemical reaction:
the total mass of reactant = the total mass of products. - 6Law of conservation of massThe total mass of the products formed in a reaction is equal to the total mass of the reactants.
This can appear wrong if it appears to lose mass. It is due to gas that has escaped into the air. - 7How to make an equation balancedThere must be the same number of each type of atom on each side of a balanced symbol equation. When balancing a chemical equation, you can never change a chemical formula.
- 8Adding state symbols to equationsAdding state symbols give extra information in balanced symbol equations. There are (s) for solids, (g) for gases and (aq) for aqueous solutions.
- 9MixtureSomething made up of two or more substances that are not chemically combined together. Mixtures have no fixed composition and there are no chemical bonds between atoms of the different substances in a mixture. Mixtures can be separated by physical means such as filtration, crystallisation and simple distillation.
- 10FiltrationUsed to separate substances that are insoluble in a particular solvent from those that are soluble in the solvent. E.g a mixture of sand, salt and water. Sand would be collected on the filter paper and water would be left with salt.
- 11CrystallisationA separation technique used to separate a solid that has dissolved in a liquid. The solution is warmed in an open container, allowing the solvent to evaporate leaving a saturated solution. As the saturated solution cools the solid will come out of the solution and crystals will start to grow. The crystals grow and can e collected and allowed to dry, The size of the crystal depends on the rate of cooling. Fast cooling-large number, small crystal. Slow cooling-small number, large crystals.
- 12DistillationA solution is heated and boiled to evaporate the solvent. The vapour is given off, then enters a condenser. It is a glass tube that acts as a cooling jacket around the inner glass from the flask. Here the out vapour is cooled and condensed back into a liquid for collection in a receiving vessel. Any remaining solids remain in the heated flask.
- 13Fractional distillationAn effective way of separating miscible liquids, using a fractionating column. The separation is possible because of the different boiling points of the liquids in a mixture.
- 14Paper chromatographyIt separates mixtures of substances dissolved in a solvent as they move up a piece of chromatography paper. The different substances are separated because of the different solubilities in the solvent used.
- 15How and why the atomic model has changed over timeThe ideas about atoms have changed over time. New evidence has been gathered from the experiments of scientists which has helped improved the understanding of the atom shape.
- 16Who proposed key ideas about the atomKey ideas were proposed by John Dalton, J.J Thomson, Ernest Rutherford and Niels Bohr.
- 17Structure of an atomAtoms are made up of protons, neutrons and electrons. Atoms carry an equal number of protons and electrons, so carry no overall charge.
- 18ProtonsProtons have a positive charge. The relative charge on a proton is +1. They are found inside the nucleus. Their relative mass is 1.
- 19NeutronsNeutrons have a neutral charge. Their relative charge is 0. They are found inside a nucleus. Their relative mass is 1.
- 20ElectronsElectrons have a negative charge. The relative charge on electrons is -1. They orbit the nucleus. Their relative mass is very small (it would take 2000 electrons to have the same mass as a proton or neutron)
- 21How to represent an atom's atomic number and mass numberYou can represent the atomic number and mass number of an atom using the notation: 24/12Mg, where magnesium's atomic number is 12 and its mass number is 24.
- 22What the atomic number and mass number of an atom representAtomic number = number of protons(electrons)
Mass number = number of protons + neutrons
They are placed on the periodic table by atomic number (eg. argon atomic number is 18) - 23IonsIf an atom gains electrons they form negative ions. If atoms lose electrons they form positive ions.
- 24IsotopesIsotopes are atoms of the same element with different numbers of neutrons. They have identical chemical properties, but physical properties, such as density, can differ.
- 25How electrons are arranged in an atomThe electrons in an atom are arranged in shells(energy levels). The 1st shell can hold up to 2 electrons. The 2nd shell can hold up to 8 electrons. The 4th shell starts to occupy after 8 electrons occupy the 3rd shell. The number of electrons in the outermost shell of an electron determines the way in which the element reacts.
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- Year 9 Chemistry FlashCards sobre Atomic Structure. AQA Chapter 1, criado por Miles McIntosh em 09-07-2017.
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- Miles McIntosh
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