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Science 7 - Coggle Diagram

- - - - The particles in solids are very densely packed together. It makes it difficult for the volume of a solid to be smaller. Solids have a fixed shape because attractive forces hold the particles together. These forces stop it from flowing. It can only vibrate. This means the solids can't flow.
      - The volume of a liquid cannot be changed. The particles care very close together however, they can move past each other. The attractive forces between the particles are weak enough to allow them to move but strong enough to hold.
      - Particles in a gas are very seperate from each other so they can move very quickly in all direction. The particles can move easily because there are no attractive forces between them. This means that gas has no fixed shape or volume.
  - - - There are many different types of atom. Scientists have discovered 94 different types of atom that occur naturally in the universe. Another 24 kinds of atom have been made in laboratories.
      - Some substances are made up of just a single kind of atom. A substance made of just one kind of atom is called an element. For example, carbon is made only of carbon atoms. Gold is made only of gold atoms. Silver is made only of silver atoms. Carbon, gold and silver are examples of elements.
      - Each type of atom has different properties. This is why different elements have different properties.
      - In six of the elements, such as neon (which is a gas), atoms move around freely, not attached to one another. But in most elements, such as gold and other metals, atoms are packed closely together.
      - In a small number of elements, such as oxygen and sulfur, atoms join together to form small particles. An oxygen particle is made from two oxygen atoms. A sulfur particle is made from eight sulfur atoms.
      - Scientists have developed a very useful way of arranging the elements. This is called the Periodic Table.
      - The full Periodic Table containing all of the 118 known elements is very large and complex. (There may be one on the wall of your science laboratory.) You are just going to look at the first 20 elements.
    - - The Periodic Table is organised into rows and columns. The rows are called periods. The columns are called groups.
      - The atoms are organised so that, as you read across each row (period) from left to right, the atoms increase in mass. Hydrogen atoms have the smallest mass, then helium atoms, then lithium atoms, and so on.
      - Each of the elements has been given a symbol. This is a useful shorthand way of referring to them.
      - Sometimes the symbol is the first letter of the English name of the element. For example, the symbol for oxygen is O.
      - Sometimes the symbol is taken from another language. For example, the symbol for sodium is Na, from the old Latin name 'natrium'.
      - The first letter of the symbol is always upper case and the second letter, if there is one, is always lower case.