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4340553-504606819807-396131Periodic Table Summary NotesElements, compounds and mixturesElements are the simplest type of substance everything in we see in the universe is made from these elements. Compounds are made of 2 or more elements joined together. Substances are made up of atoms. Atoms are the smallest type of particle in substances. Elements contain only one type of atom.A molecule is made up of 2 or more atoms joined together.Elements can exist as solids, liquids or gases. Every element known to man is listed in the Periodic Table. This is split into metals and non-metals.Every element in the periodic table has symbol which represents it and an atomic number. These are unique to every element; no element has the same symbol or atomic number.Groups of the Periodic TableThe rows of elements are called periods.The columns are called groups. Elements in the same group react in similar ways.Group 1 metals all react with water and are called the Alkali Metals.Group 2 metals are reactive with acid and are called the Earth Metals.Group 7 elements are reactive and are known as the Halogens.Group 8 elements are completely unreactive and are known as the Noble Gases.Properties of Metals and Non-metals46350601600500Metals:Are shiny when polished.Can conduct electricity and heat. Are solids at room temperature (except mercury).Non-metals:46478933089700Can be solid, liquid or gas.Most have low melting points.Are poor conductors of electricity and heat. Solids are brittle.Naming CompoundsThe names of compounds depend on the elements that make them. If we look at the elements present then we can name the compound. When naming compounds the metal atom is usually the first part of the name and the non-metal atom forms the second part of the pounds that end in “ide” contain only two elements such as Sodium Chloride which contains sodium and chlorine. Compounds that end in either “ate” or “ite” contain three elements with one of the always oxygen.Writing Chemical Word EquationsWe can write out any chemical reaction as a chemical word equation using just the names of the chemicals and some symbols.The reactants go on the left and the products go on the right.Examples:Magnesium reacts with hydrochloric acid to produce hydrogen gas and the compound magnesium chloride.magnesium + hydrochloric acid magnesium chloride + hydrogenSeparating MixturesMixtures can be easily separated as they are not chemically joined. Iron can be separated from other elements using a magnet. Soluble solids can be separated from liquids by evaporation of the liquid. Insoluble solids can be separated from liquids by filtration.ACIDS & ALKALIS Acids and alkalis can be found all around us. Some are useful and are found in food and in our bodies. For example, vinegar and vitamin C are acids and carbonic acid is in fizzy drinks. Hydrochloric acid is in our stomachs to help us digest food. However, many are also dangerous, as both acids and alkalis are corrosive. pH Scale and Indicators We can tell whether something is an acid or an alkali using indicators. These are special chemicals which change colour depending on whether the substance is an acid or alkali.Universal indicator and pH paper have a full range of colours which means they can tell you whether something is an acid, alkali or neutral. It can also tell how acidic an acid is or how alkaline an alkali is. When added to a substance the Universal indicator or pH paper changes colour. These colours are then related to a number using the pH scale.Acids, such as hydrochloric acid, have a pH less than 7.Alkalis, such as sodium hydroxide, have a pH greater than 7Neutral substances, such as water, have a pH equal to 7.pH of Household SubstancesReactions of AcidsWhen acids react, their pH increases to 7. There are 4 main reactions of acids.1. alkali (metal hydroxide) + acid → salt + water2. metal oxide + acid → salt + water3. metal carbonate + acid → salt + water + carbon dioxide4. reactive metals (MAZINTL) + acid → salt + hydrogenThe first 3 reactions are known as neutralisation reactions.Number 4 is a displacement reaction.The name (and type) of salt depends on which acid is involved.Uses of Neutralisation ReactionsThere are many examples of neutralisation reactions in the world around us: Lime (an alkali) is added to acidic soil and lakes to increase the pH. Acid rain can cause the soil and lakes to become acidic.Toothpaste is alkaline to neutralise the acid produced by plaque on our teeth. This acid causes our teeth to rot.Bee stings are acidic, so are treated with an alkali, such as milk of magnesia. Wasp stings are alkaline, so are treated with an acid, such as vinegar.Indigestion is caused by too much acid in our stomach. So, indigestion tablets are alkaline and decrease the acidity.Ammonium nitrate is a salt made by a neutralisation reaction. This is an important fertiliser for plants. ................
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