An element is a pure substance made of only one type of atom, distinguished by its atomic number. An atom is the smallest unit of an element, and metals are elements that conduct heat and electricity well while being malleable. Non-metals are generally poor conductors that are brittle. The periodic table displays all known elements arranged by atomic structure. Compounds are formed by two or more elements chemically bonding together. Chemical reactions lead to new substances through breaking and forming of bonds.
2. elements An element is a pure substance consisting of only one type of atom. It is distinguished by it’s atomic number, or the number of protons in it’s nucleus.
3. atoms An atom is a basic unit of matter. Also it is the smallest recognized division of a chemical element.
4. metals A metal is a chemical element, compound or alloy, characterised by high electrical and heat conductivity. It’s also ductile (it can be stretched without breaking) and tensile (it can be bent without breaking).
5. non-metals A non-metals (such as hydrogen & carbon) are poor conductors of heat & electricity, and are dull and brittle in solid form. The usually have lower densities, freezing points and boiling points than metals.
6. the periodic table The periodic table is a display of all the pure chemical elements. The current standard table contains 117 elements.
7. compounds A compound is two or more different elements fused together. Some examples are aluminium, baking soda and tin.
8. chemical reactions A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Examples are a plant changing sunlight into energy or metal going rusty.
9. identification You can tell if there is a chemical reaction happening because either heat, light, precipitate or gas will be produced.
10. Chemical changes A chemical changes is when the bonds of an object are broken and new bonds are formed, creating a new substance (e.g. cooking, corn kernals into popcorn).
11. physical changes In a physical change, the substance doesn’t change chemically at all, but takes on a different form (e.g. water freezing and melting)
12. reaction rate A reaction rate is the rate that two substances combine to form a chemical reaction. For example, iron rusting is a slow reaction rate. Fire burning a log into charcoal is a fast reaction rate.
13. Factors of reaction rate . Concentration – how diluted or pure the substance is. . Temperature – how hot/cold the environment is. . Catalyst – whether or not there is another substance to provide a pathway. . Surface area – powder is going to dissolve faster than a tablet.
