Bonding
3.1 The Nature of Ionic Bonding
3.1 The nature of ionic bonding
- Ionic bonding is the electrostatic attraction between positive
and negative ions. 3.2 covalent bonding
- Metals have 1, 2 or 3 electrons in their outer shell so the 3.3 metallic bonding
easiest way to get a full shell is to lose these electrons. Non-
metals have spaces in their outer energy levels so the easiest 3.4 electronegativity – bond polarity in
way for them to get a full shell is to gain electrons. covalent bonds
- Ionic bonding occurs between metals and non-metals.
3.5 forces acting between molecules
- Electrons are transferred from metal atoms to non-metal
atoms and positive and negative ions are formed. 3.6 the shapes of molecules and ions
- The two charged particles that result from the transfer of an 3.7 bonding and physical properties
electron are called ions. The metal is positively charged because
it has lost electrons and the non-metal negative because it has gained electrons. The two ions are
attracted to each other and to other oppositely charged ions in the compound by electrostatic forces.
- Ionic compounds form lattice structures.
- The strength of the bond increases when the charge on the ions increase.
- Properties of ionic compounds
o Solid at room temperature
o Giant structures
o High melting point – to melt an ionic compound energy must break up the lattice
o Conduct electricity when molten or aqueous but not when solid – in a liquid state the ions are
free to move and carry current.
o Brittle
- Valencies to learn
o NO3- Nitrate
o CO32- Carbonate
o SO42- Sulfate
o OH- Hydroxide
o NH+ Ammonia
o PO43- Phosphate
3.2 Covalent Bonding
- Covalent bonding is the strong electrostatic attraction between a shared pair of electrons and the
nuclei of the bonded atoms.
- A covalent bond forms between two non-metal atoms.
- The atoms share some of their outer shell electrons so that each atom has a stable noble gas
arrangement.
- You can represent one pair of shared electrons in a covalent bond by a line, Cl–Cl
- In a double bond four electrons are shared. You can represent the two pairs of shared electrons by a
double line, O=O.
- Properties of covalent molecules
o Covalent molecules have low melting temperatures because there is only weak attraction
between the molecules.
o They are poor conductors of electricity because the molecules are overall neutral, no charged
particles to carry the current.
o If they dissolve in water and remain as molecules the solutions do not conduct electricity.
- Sometimes one of the atoms contributes both of the bonding electrons. When this happens a dative
covalent bond forms, also called co-ordinate bonding.
3.1 The Nature of Ionic Bonding
3.1 The nature of ionic bonding
- Ionic bonding is the electrostatic attraction between positive
and negative ions. 3.2 covalent bonding
- Metals have 1, 2 or 3 electrons in their outer shell so the 3.3 metallic bonding
easiest way to get a full shell is to lose these electrons. Non-
metals have spaces in their outer energy levels so the easiest 3.4 electronegativity – bond polarity in
way for them to get a full shell is to gain electrons. covalent bonds
- Ionic bonding occurs between metals and non-metals.
3.5 forces acting between molecules
- Electrons are transferred from metal atoms to non-metal
atoms and positive and negative ions are formed. 3.6 the shapes of molecules and ions
- The two charged particles that result from the transfer of an 3.7 bonding and physical properties
electron are called ions. The metal is positively charged because
it has lost electrons and the non-metal negative because it has gained electrons. The two ions are
attracted to each other and to other oppositely charged ions in the compound by electrostatic forces.
- Ionic compounds form lattice structures.
- The strength of the bond increases when the charge on the ions increase.
- Properties of ionic compounds
o Solid at room temperature
o Giant structures
o High melting point – to melt an ionic compound energy must break up the lattice
o Conduct electricity when molten or aqueous but not when solid – in a liquid state the ions are
free to move and carry current.
o Brittle
- Valencies to learn
o NO3- Nitrate
o CO32- Carbonate
o SO42- Sulfate
o OH- Hydroxide
o NH+ Ammonia
o PO43- Phosphate
3.2 Covalent Bonding
- Covalent bonding is the strong electrostatic attraction between a shared pair of electrons and the
nuclei of the bonded atoms.
- A covalent bond forms between two non-metal atoms.
- The atoms share some of their outer shell electrons so that each atom has a stable noble gas
arrangement.
- You can represent one pair of shared electrons in a covalent bond by a line, Cl–Cl
- In a double bond four electrons are shared. You can represent the two pairs of shared electrons by a
double line, O=O.
- Properties of covalent molecules
o Covalent molecules have low melting temperatures because there is only weak attraction
between the molecules.
o They are poor conductors of electricity because the molecules are overall neutral, no charged
particles to carry the current.
o If they dissolve in water and remain as molecules the solutions do not conduct electricity.
- Sometimes one of the atoms contributes both of the bonding electrons. When this happens a dative
covalent bond forms, also called co-ordinate bonding.
