6.1 Elements
Elements
There are over a hundred different types of atom, and these are called elements. Each element has a special name. For example carbon, oxygen and hydrogen are all elements.
Lead and gold are elements too. A piece of pure gold contains only gold atoms. A piece of pure lead contains only lead atoms.
Chemical reactions join or split atoms to rearrange them. But they cannot change one element into another element, or anything simpler. A chemical reaction cannot turn lead into gold, becuse it can't change the atoms into different elements.
There are over a hundred different types of atom, and these are called elements. Each element has a special name. For example carbon, oxygen and hydrogen are all elements.
Lead and gold are elements too. A piece of pure gold contains only gold atoms. A piece of pure lead contains only lead atoms.
Chemical reactions join or split atoms to rearrange them. But they cannot change one element into another element, or anything simpler. A chemical reaction cannot turn lead into gold, becuse it can't change the atoms into different elements.
Watch this clip to help you understand Elements!
The Periodic Table
All the different elements are arranged in a chart called the periodic table.
All the different elements are arranged in a chart called the periodic table.
- The horizontal rows are called periods.
- The vertical columns are called groups.
- Elements in the same group are similar to each other.
- The metals are on the left and the non-metals are on the right.
- One non-metal, hydrogen, is often put in the middle.
- The main groups are numbered from 1 to 7 going from left to right, and the last group on the right is group 0.
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Metals
Iron, magnesium and gold are examples of metal elements.
All metals have these properties in common:
These are iron, cobalt and nickel. Steel is a mixture of elements but mostly iron, so it is also magnetic. The other metals are not magnetic.
Iron, magnesium and gold are examples of metal elements.
All metals have these properties in common:
- They are shiny, especially when they are freshly cut.
- They are good conductors of both heat and electricity.
- They can be bent without breaking (they are malleable).
- they are solid at room temperature, except mercury, which is liquid at room temperature
- they are hard and strong
- they have a high density (they feel heavy for their size)
- they make a ringing sound when they are hit (they are sonorous)
These are iron, cobalt and nickel. Steel is a mixture of elements but mostly iron, so it is also magnetic. The other metals are not magnetic.
- Mercury is the only liquid metal at room temperature.
Non-metals
Oxygen, carbon, sulphur and chlorine are examples of non-metal elements.
All non-metals have these properties in common:
Oxygen, carbon, sulphur and chlorine are examples of non-metal elements.
All non-metals have these properties in common:
- they are dull (not shiny)
- they are poor conductors of heat and electricity (they are insulators)
- they are weak and brittle (they easily break or shatter)
- they have a low density (they feel light for their size)
- they do not make a ringing sound when they are hit (they are not sonourous)
- Eleven non-metals are gases at room temperature, including oxygen and chlorine.
- One non-metal, bromine, is a liquid at room temperature.
- The other non-metals are solids at room temperature, including carbon and sulphur.