What is a covalent bond?
A bond formed between oppositely charged ions
A bond formed when two atoms share a pair of electrons
A bond formed by delocalised electrons
How many different types of atom are in an NH3 molecule?
2
3
4
In a dot and cross diagram, what does each dot represent?
A neutron
A proton
An electron
What is the greatest number of covalent bonds that one carbon atom can form?
How many electrons are shared in a double bond?
8
When a substance made of small molecules boils, what does the energy have to overcome?
Intermolecular forces
Ionic bonds
Covalent bonds
Which statement best explains why substances made of small molecules cannot conduct electricity?
They have no charged particles that are free to move from place to place
They cannot move from place to place
They have no charged particles
Which of these substances has a giant covalent structure?
Silicon dioxide
Water
A polymer
What type of bond joins the atoms together in a polymer molecule?
Covalent
Ionic
Which statement best explains why diamond has a high melting point?
It has strong covalent bonds
A large amount of energy is needed to break its strong covalent bonds
A large amount of energy is needed to break its bonds