Chemistry Topic 1

Chemistry Topic 1

1. Atoms and their structure

   • consist of electrons surrounding a nucleus (in shells). The nucleus contains protons and neutrons
   • Atomic number = number of protons in an atom

2. Sub Atomic Particles

   • A particle smaller than an atom
   • Neutrons = no charge Protons = +1 Electrons = -1

3. Isotopes

   • Isotopes are atoms of an element with different numbers of neutrons.

4. Chemical Equations

   • Subscript = number after and below the element letter to show how many of each element there is
   • Superscript = shown when the atomic mass is next to an element in the periodic table

5. Mixtures

   • Filtration = If a substance does not dissolve in a solvent, we say that it is insoluble. For example, sand does not dissolve in water – it is insoluble.
   • Evaporation = used to separate a soluble solid from a liquid e.g. copper sulfate is soluble in water
   • Simple distillation = a method for separating the solvent from a solution. For example, water can be separated from salt solution
   • Fractional distillation = a method for separating a liquid from a mixture of two or more liquids. For example, liquid ethanol can be separated from a mixture of ethanol and water
   • Chromatography = a method for separating dissolved substances from one another. It is often used when the dissolved substances are coloured, such as inks, food colourings and plant dyes. It works because some of the coloured substances dissolve in the solvent used better than others, so they travel further up the paper.

6. Models of the atom

   • Rutherford's Plum Pudding Model
   • Nuclear Model

7. The Periodic Table

   • Atoms arranged in order of atomic number

8. Group1 - The Alkali Metals

9. Group 7 - The Halgoens

10. Group 0 - The Noble Gases