Define an ion
A charged particle formed when an atom gains or loses electrons
Define an ionic bond
A chemical bond between oppositely charged ions in which the metal loses electrons (cation) to the non metal (anion)
Define a molecular ion
An ion formed by two or more atoms covalently bonded
Define a covalent bond
A chemical bond that occurs between two non metals which share a pair of electrons from their outer shells
Define diatomic
Two atoms covalently bonded together
Define Metallic bonding
The attraction between the positive ions in a regular lattice and the delocalised electrons
Group 8 or 0 do not form ions. Why not?
They already have a full outer shell and therefore do not need to lose or gain electrons
Display the structural format for hydrogen
H-H
What kind of bonding would you expect between the following pairs of elements ? K and Cl N and H S and O Na and F
K and Cl - Ionic
N and H - Covalent
S and O - Covalent
Na and F - Ionic
Draw a diagram showing the structure of a metal such as copper
Delocalised electrons (e-) Positive metal ions ( Cu2+)
Cation definition
Positively charged ion
Anion definition
Negatively charged ion
Define molecule
A molecule is two or more atoms covalently bonded
Features of covalent bonds (2)
- Strong
- Substantial energy is required to break covalent bonds
Feature of Ionic bonds
They require a lot of energy to break them apart
Using electronic structures explain how atoms of chlorine and calcium become bonded in their formation of the compound calcium chloride (5)
- The calcium atom has an electronic configuration of 2,8,8,2.
- The chlorine atom has an electronic configuration of 2,8,7.
- The calcium atom transfers two electrons to 2 chlorine atoms producing one calcium ion with an electronic configuration of 2,8,8
- and two chloride ions with an electronic configuration of 2,8,8.
- The calcium ion (Ca2+) And the chloride ions (Cl-) are held together by strong electrostatic forces of attraction
Allotropes
Different forms of the same element in the same physical state
Why does water have a much lower melting point than calcium fluoride ? (2)
- Water molecules are held together by weak forces of attraction ( van der Waals forces) which take only a little amount of energy to break
- Calcium fluoride is an ionic compound made from ions held together by strong electrostatic forces of attraction which take a lot of energy to break
