science revision

1. Reactions of alkali metals with water

1.1. Lithium When lithium is added to water, lithium floats. It fizzes steadily and becomes smaller, until it eventually disappears.

1.2. Sodium When sodium is added to water, the sodium melts to form a ball that moves around on the surface. It fizzes rapidly, and the hydrogen produced may burn with an orange flame before the sodium disappears.

1.3. Potassium When potassium is added to water, the metal melts and floats. It moves around very quickly on the surface of the water. The hydrogen ignites instantly. The metal is also set on fire, with sparks and a lilac flame. There is sometimes a small explosion at the end of the reaction.

1.4. Strong alkalis The hydroxides formed in all of these reactions dissolve in water to form alkaline solutions. These solutions turn universal indicator purple, showing they are strongly alkaline. Strong alkalis are corrosive. Care must be taken when they are used - goggles and gloves should be worn.

2. periodic table

2.1. mandleev invented the periodic table

2.2. new elements are being invented every year and being added to the periodic table

2.3. the groups are organised in the increasing a atomic number

2.4. elements in the same group are similar to each other

3. Metals

3.1. Iron, magnesium and gold are examples of metal elements. Metals have properties in common.

3.2. They are: .shiny, especially when they are freshly cut

3.3. good conductors of heat and electricity

3.4. malleable (they can be bent and shaped without breaking)

3.5. Most metals also have other properties in common.

3.6. They are: solid at room temperature, except mercury

3.7. hard and strong

3.8. they have a high density

3.9. they are sonorous