What is covalent bonding?
A bond between non-metals by sharing electrons.
What is ionic bonding?
When a metal atom loses electrons and a non-metal atom gains electrons, the oppositely charged ions attract each other.
What element group combine using ionic bonding?
Group 1 metals and Group 7 non-metals.
Ionic bonding holds oppositely charged ions together in giant structures.
What are they?
Ions form a giant structure or lattice. The lattice is very regular because the ions are packed together neatly.
Why is calcium chloride CaCl2?
Calcium ions is 2+, but Chloride ion is 1- and the charges on the ions must always cancel each other out.
How are the atoms arranged in a metal?
The atoms in a metallic element are the same size. They form giant structures of layers of atoms arranged in a regular pattern.
What forces hold metal atoms in place in their giant structures?
The electrons in the highest energy level (outer electrons) are delocalised.
The strong electrostatic forces between the delocalised electrons and the positively charged metal ions hold the metal together.
Explain, in terms of particles, why liquid iodine does not conduct electricity (2 marks).
Simple molecule has no overall charge so can't carry electrical charge (1). No delocalised electrons to move through the substance (1).
Silicon dioxide has a very high melting point.
Other substances are added to silicon dioxide to make glass. Glass melts at a lower temperature than silicon dioxide.
Describe the structure of a metal (3 marks).
-Lattice/regular pattern/layers/giant structure/close-packed arrangement.
-Of positive ions or atoms.
-With free electrons.