Chemistry- AQA GCSE- Covalent bonding
Describe what a covalent bond is
A covalent bond is a strong bond between two non-metal atoms. It consists of a shared pair of electrons. A covalent bond can be represented by a straight line or dot-and-cross diagram.
What is a molecule?
A molecule is a collection of two or more atoms held together by chemical bonds.
How many covalent bonds can hydrogen and chlorine atoms form?
Hydrogen atoms and chlorine atoms can each form one covalent bond
How many covalent bonds does hydrogen and noble gases from group 1 form?
Hydrogen forms one covalent bond. The noble gases in Group 0 do not form any.
What do substances with covalent bonds often form?
Substances with covalent bonds often form molecules with low melting and boiling points, such as hydrogen and water.
How do you work out how many covalent bonds an element will form?
The number of covalent bonds is equal to eight minus the group number
Where do the electrons in a covalent bond come from?
They come from the highest occupied energy level
How many electrons are involved in each covalent bond?
Two electrons
How many covalent bonds does carbon form?
carbon atoms can each form four covalent bonds.
How many covalent bonds does nitrogen form?
nitrogen atoms can each form three covalent bonds
How many covalent bonds can oxygen atoms form?
oxygen atoms can each form two covalent bonds. Two pairs of electrons are shared in a water molecule