Atoms, Elements ,Compounds and Mixtures

• The periodic table of elements contains all the elements that are used in chemistry.
• Sodium, chlorine, copper, and helium are all elements from the periodic table.
• Sodium is a solid metal, chlorine is a gas that's a non-metal, copper is a metal, and helium is a gas that's a non-metal.
• All elements are made of only one type of atom.
• Sodium metal reacts with chlorine gas, producing hydrogen and a bright orangey yellow color.
• Word equations can be used to show reactions that happen, for example, sodium plus chlorine makes sodium chloride.
• Elements can sometimes react to form compounds, a compound is two or more elements joined together by a chemical reaction joined together by chemical bonds.
• The properties of a compound are different to the properties of the elements in it.
• Elements are made of one type of atom only, for example, sodium is a solid metal and chlorine gas is made of pairs of atoms.
• Chlorine gas is a poisonous gas that can cause irritation in the eyes and damage to the lungs if breathed in large amounts.
• Sodium chloride, also known as common salt, is the new substance formed in the reaction between sodium and chlorine.
• Sodium chloride is the kind of salt used on food.
• The metals and non-metals are located on different sides of the periodic table, with everything to the right of a certain line being non-metals and everything to the left being metals.
• All metals are hard and shiny, with the exception of mercury which is shiny but liquid.
• Metals have a high density, meaning they have a large mass for the volume they occupy, and feel heavy.
• Non-metals, if they are solid, are not shiny and are dull in appearance.
• Metals are good conductors of electricity, while non-metals are poor conductors and insulators.
• Metals are also good conductors of heat energy, while non-metals are poor conductors and insulators of heat energy.
• Metals are malleable, meaning they can be bent or hammered into shape, while non-metals tend to crack or shatter if they are solid and are brittle.
• Metals have high melting and boiling points, requiring a lot of energy to melt them, while non-metals tend to have lower melting and boiling points and some are even gases at room temperature.
• Metals are sometimes magnetic, with nickel, iron, and cobalt being magnetic, while non-metals are all not magnetic and do not get attracted by magnets.
• Metals are ductile, meaning they can be drawn into long wire shapes, while non-metals are not ductile and cannot be drawn or pulled into wire shapes.