GCSE Additional Science - C5 Chemicals of the natural environment definitions

Lithosphere

The rigid outer layer of the Earth, made up of the crust and the part of the mantle just below it.

Crust

The outer layer of the lithosphere.

Mantle

The layer of rock between the crust and the outer core of the Earth

Hydrosphere

All the water on Earth. This includes oceans, lakes, rivers, underground reservoirs and rain water.

Biosphere

All the living organisms on Earth; includes plants, animals and microorganisms.

TIP

the "bio" in biosphere may connect with plants etc.

Electrostatic attraction

The force of attraction between objects with opposite electric charges. eg a positive ion attracts a negative ion.

Covalent bonding

Strong attractive forces that hold atoms together in molecules. Covalent bonds form between atoms of non-metallic elements.

abundant

Abundant measures how common an element is. Silicon is abundant in the lithosphere. Nitrogen is in the atmosphere for example.

relative atomic mass

The mass of an atom of an element compared to the mass of an atom of carbon.

Relative formula mass

The combined relative atomic masses of all mass the atoms in a formula.

To find the relative formula mass of a chemical, you just add up the relative atomic masses of the atoms in the formula.

electrolysis

Splitting up a chemical into its elements by passing an electric current through it.

electrode

A conductor made of a metal or graphite through which a current enters or leaves a chemical during electrolysis. 

Electrons flow into the negative electrode (cathode) and out of the positive electrode (anode).

ionic compound

Compounds formed by the combination of a metal and non-metal. They contain positively charged metal ions and negatively charged non-metal ions.

ionic bonding

Very strong attractive forces that hold the ions together in an ionic compound. 

The forces come from the attraction between postively and negatively charged ions.

giant ionic structure

The structure of solid ionic compounds. There are no individual molecules, but millions of oppostely charged ions packed closely together in a regular, three dimentional arrangement.

giant covalent structure

A giant three dimentiosional arrangement of atoms that are held together by covalent bonds. Silicon dioxide and diamond are examples of elements that do have giant covalent structures.

Quartz

A crystalline form of silicon dioxide SiO2

carbon cycle

The cycling of the element carbon in the environment between the atmosphere, biosphere, hydrosphere and lithosphere. The element exists in different compounds in these spheres. In atmosphere it is mainly present as carbon dioxide

nitrogen cycle

Continual cycling of nitrogen, one of the elements that is essential for life. By being converted into different forms, nitrogen is able to cycle between the atmosphere, lithosphere,hydrosphere & biosphere.

natural cycle

(in the environment)

The cycling of an element between the atmosphere, hydrosphere and biosphere as a result of natural processes.

ores

A natural mineral that contains enough valuable minerals to make it profitable to mine.

oxides

A compound of an element with oxygen.

metallic bonding

Very strong attractive forces that hold metal atoms together in a solid metal. The metal atoms lose their outer electrons and form positive ions. The electrons drift freely around the lattice of positive metal ions and hold the ions together.