CHEMISTRY REVISION
Periodic table * All the elements on the Earth are on the Periodic Table. * They are arranged according to patterns in their properties e.g. The masses of their atoms * The relative atomic mass is the mass of an atom in relation to hydrogen e.g. Helium has an atomic mass of 4 which means it has 4x the mass of hydrogen * Each period starts with a metal and ends with a non-metal
Alkali metals * The alkali metals (Group 1 in the periodic table) are Lithium, Sodium, Potassium, Rubidium, Caesium and Francium. This is in order of reactivity from the least to most reactive. * Alkali metals are different from other metals as they are not very dense and can be cut easily and they produce an alkali reaction with water. * They oxidise in the air and in water they make hydrogen and hydroxide. * They are kept in oil to make sure that it does not react with oxygen in the air * They all have low densities * The more reactive the metal the less melting and boiling point they have which is why melting and boiling point of alkali metals do down the higher the period number. * Their surfaces shiny when freshly cut but tarnish rapidly in moist air due to reaction with oxygen * React with water to form hydrogen and an alkaline solution of a hydroxide with the formula MOH (M represents Li, Na, K etc.) * React vigorously with chlorine to form colorless, crystalline salts with the formula MCl (M represents Li, Na, K etc.)
* Anyone using a corrosive substance should wear gloves and eye protection, such as goggles or a face shield. * Anyone using an irritant substance should wear eye protection such as goggles, and they should take care to wash any spills off their skin immediately. * Anyone who uses a toxic chemical needs to take great care. They should wear gloves and eye protection, and they may wear a mask over their mouth and nose, or handle the chemical in a fume cupboard. * Anyone using a harmful substance should wear eye protection such as goggles, and they should take care to wash any spills off their skin immediately. * In addition to the normal precautions of wearing eye protection, anyone using a highly flammable substance should take care to keep it away from flames and sparks, and also from oxidising substances. * In addition to the normal precautions of wearing eye protection, anyone using an oxidising substance should take care to keep it away from flammable substances, including clothing.
Lithium (Li): * Shiny grey. * Soft, can be cut. * Less density than water. * Stored in oil. * Melting point 181 degrees. * Boiling point 1342 degrees. * When reacting with oxygen it makes Lithium Oxide. * When burned it creates a orange-pink flame. * When reacting with water it makes Lithium Hydroxide + Hydrogen and turns the water turn purple. * When reacting with chlorine it produces Lithium Chloride and makes a small orange flame and white residue (the lithium chloride)
Sodium (Na): * Very shiny grey * Softer than Lithium, can be cut * Less dense than water * Stored in oil * Melting point 98 degrees * Boiling point 883 degrees * When reacting with oxygen it makes Sodium Oxide * When burning it creates a large bright orange flame * When reacting with water it produces Sodium Hydroxide + Hydrogen and makes water turn a light purple. The reaction is more vigorous than the Lithium. * When reacting with Chlorine it produces Sodium Chloride (table salt) and makes a bright luminous yellow flame and a white (sodium chloride) residue.
Potassium (K): * Very very shiny grey * Softer than Lithium and sodium, can be cut * Less dense than water * Stored in oil * Melting point 63 degrees
