CHEMISTRY

CHEMISTRY

1. On the periodic table, a zig zag line seperates metals (on the left) from non-metals on the right. (BALGA)

   • Metals are solid, hard, have metallic shine, can be beaten into thin sheets, can be drawn into wires, have high melting points, have high boiling points, are good conductors of heat, good conductors of electricity and produce sound when beaten.
     • Non metals may be solids, liquids or gases. Non metals are soft. They do not have metallic shine, cannot be beaten into thin sheets, can not be drawn into wires, have low melting/boiling points, bad conductos of heat, bad conductors of electricy and produce no sound when beaten.
   • An atom is the smallest part of an element. A molecule is a small group of atoms joined together. If the atoms are the same then it's a molecule of an element. if there are different atoms it's a compound. an element is something made up of only one type of atom. the atoms can be joined together or single. a compound is made up of 2 or more types of atom.
     • Things which contain only one type of atom are called elements. Compounds always contain more than one type of atom. The chemical name for common salt is sodium chloride made up of two parts, which makes it a compound.

2. When atoms join together either in an element or a compound they are then called molecules.

3. When chemical reactions occur particles just rearrange. The total number of particles have rearranged and therefore the masss is constant. This is law of conservation of mass.

   • Signs of chemical reactions: change of color. formation of gas. formation of precipitate, change of temperature, heat/energy is produced.

4. How rocks are useful

   • Granite is used for kitchen worktops. Sandstone is good building material and so is limestone. Marble is used to carve statues.

5. Rocks are made up from minerals. The texture of a rock depends on the size and shape of grains.