What is a covalent bond? A bond formed by sharing a pair of electrons between two non metals
attain a Nobel gas structure Draw a dot cross diagram to illustrate the bonding in H2
Draw a dot cross diagram to illustrate the bonding in Cl2
Draw a dot cross diagram to illustrate the bonding in H2O Draw a dot cross diagram to illustrate
the bonding in CH4 Draw a dot cross diagram to illustrate the bonding in NH3
Draw a dot cross diagram to illustrate the bonding in HCl
Describe the differences in volatility, solubility and electrical conductivity between ionic and covalent compounds
property volatility Solubility
Electrical conductivity Ionic compound Not volatile
Most are soluble in water but insoluble in organic solvents such as cyclohexane
The solids to not conduct. When molten or dissolved in water they do conduct
Simple covalent volitile Most are insoluble in water but soluble in
organic solvents Generally do not conduct Draw a dot cross diagram to illustrate
the bonding in N2 Draw a dot cross diagram to illustrate the bonding in C2H4
Draw a dot cross diagram to illustrate the bonding in CH3OH
Draw a dot cross diagram to illustrate the bonding in CO2 Explain the differences in melting point
and boiling point of ionic and covalent compounds in terms of attractive forces Because there are only weak forces of attraction
between simple covalent molecules, they can easily beak free of the solid structure, so melting points are low. Particles in the liquid are only weakly held
together so boiling points are also low In ionic compounds melting points are high because of the strong attraction between ions
Explain the term ionic lattice In solids ions are regularly arranged in a lattice of alternating positive and negative
ions. Ionic compounds are said to have giant ionic structure
What are giant covalent structures Macromolecules are giant covalent structures where many atoms are held
together by strong covalent bonds, unlike simple covalent molecules such as chlorine and water
Describe the giant covalent structures in diamond and its uses Diamond is a form of carbon in which every carbon
atom is bonded to four other carbon atoms by strong covalent bonds Because of its giant structure and strong covalent bonds, diamond:
1. Is the hardest natural substance 2. Has a high melting point 3. Does not conduct electricity It is used in cutting tools and drill bits
Describe the giant covalent structures in graphite and its uses
Graphite is another form of carbon Each carbon atom is bonded by three strong covalent bonds to make a giant structure consisting of layers of hexagons The layers can slide over each other because there are no covalent
bonds between them, just weak forces of attraction between the layers This makes graphite soft and a good lubricant Graphite conducts electricity because the fourth electron of every
carbon atom is unbounded and moves along the sea of delocalised electrons Describe the macromolecular structure
of silicon(IV) oxide (silicon dioxide)
Silicon oxide has a structure similar to diamond, except instead of carbon atoms,
there are alternating silicon and oxygen atoms This means it has similar properties to diamond
Describe the similarity in properties between diamond and silicon(IV) oxide related to their structures
Hard High melting point
Describe metallic bonding Describe metallic bonding
Metals form a lattice of positive ions in a sea of electrons Why are metals good conductors of
electricity? Many metals conduct electricity because the electrons are free to move
in the delocalised sea of electrons Why are metals malleable
They are malleable because the metals ions are arranged in layers which can slide over each other
