Types Of Compounds

Question 1

Ionic melting point?

Answer 1

The melting point is high as the ionic bonds are strong, a lot of heat energy is required to overcome these bonds and loosen the Ions in the lattice turning the solid into a liquid therefore the ionic solid has a high melting point

Question 2

Ionic hard and brittle?

Answer 2

The ionic bonds are directional this means that when a force is applied the ions move and like charges line up therefore shattering the solid and this makes the ionic solid brittle

Question 3

Ionic compound?

Answer 3

Positive metal ions and negative non-metal ions are held together by strong directional ionic bonds in a 3D Lattice

Question 4

Ionic - Solid non-conductive?

Answer 4

Solid non-conductive - conductivity requires moving charged particles. in this solid there are +ve and -ve ions held in fixed positions in the lattice and because these cannot move the solid does not conduct.

Question 5

Ionic - liquid and aqueous conduct?

Answer 5

Liquid & Aqueous are conductive - however, when melted (Liquid) or dissolved in water (aqueous) the ions become free to move so they do conduct

Question 6

Metallic compound?

Answer 6

metal atoms are held in fixed positions in a 3D lattice surrounded by a sea of delocalised valence electrons. the valence e’s are free to move through the lattice in both the solid and liquid state. the strong force of attraction between the metal atoms and the sea of valence e’s is a metallic bond. this is non-directional.

Question 7

Metallic melting point?

Answer 7

the melting point is high as the metallic bond is strong, a lot of heat energy is required to loosen the attraction between the metal atoms and the sea of delocalised valence e’s turning the solid lattice into a liquid.

Question 8

Metallic malleable and ductile?

Answer 8

malleable & ductile - metallic bonds are non-directional, the attraction between the metal atoms and the sea of delocalised valence e’s is not in any particular direction. as a result the metal atoms can move past each other without breaking the metallic bond so metals are malleable and ductile.

Question 9

Metallic conductivity?

Answer 9

Conductive - Conductivity requires moving charged particles, in a metallic solid there are metal atoms and a delocalised sea of moving negatively charged electrons within the 3D lattice. as a result, a metallic solid is able to conduct in the solid and liquid state.

Question 10

Metallic solubility?

Answer 10

Not Soluble - metallic substances are generally not soluble in anything as the water-water IMF and the metallic bonds between are stronger than the water-metal atoms force and the atoms is insufficient to pull them out of their solid lattice.

Question 11

Covalent network (SiO2) compound

Answer 11

Silicon dioxide (SiO2) - the Si and O atoms are held together by strong covalent bonds in a tetrahedral arrangement so that a 3-D network exists.

Question 12

Covalent network - diamond (c) compound

Answer 12

Diamond C - the C atoms are held together by strong covalent bonds - each C is bonded to 4 other C atoms in a tetrahedral arrangement which forms a covalent network solid.

Question 13

Covalent network - graphite (c) compound

Answer 13

Graphite C - the C atoms are held together by strong covalent bonds - each C is bonded to 3 other C atoms in a 2-D hexagonal arrangement which forms layers with a free negatively charged electron per atom. The layers are attracted to each other by weak forces.

Question 14

Covalent networks melting point?

Answer 14

The melting point is high as all network covalent solids are held together by strong covalent bonds within the solid structure because the covalent bonds are strong, a lot of heat is required to loosen these bonds within the solid and cause the solid to change state to a liquid.

Question 15

Covalent networks - graphite soft?

Answer 15

Graphite soft - each C in the 2-D hexagonal arrangement is bonded to 3 other C atoms forming layers with weak intermolecular forces between the layers. these wlf’s are easily - graphite is soft and slippery and the layers can slide over each other.

Question 16

Covalent network conductivity?

Answer 16

Graphite conducts - conductivity requires moving charged particles within the solid lattice - each C atom is bound to 3 others by covalent bonds - this leaves one unbonded electron which is able to move freely through the solid and is the reason graphite is able to conduct.

Question 17

Covalent network solubility?

Answer 17

Not soluble - covalent network substances are generally not soluble in anything as the weak wlf and the covalent bonds between atoms are stronger than water’s atom force. The attraction between water and the atoms is insufficient to pull them out of their solid lattice.

Question 18

Molecular compound?

Answer 18

molecular Solids are made up of molecules within each molecule, strong covalent bonds hold the non-metal atoms together. the molecules in the Solid are held to other molecules in the solid by weak intermolecular forces (WIF’s)

Question 19

Molecular melting point?

Answer 19

the melting point is low As the WIF’s between molecules in the molecular solid are weak, only a small amount of heat energy is required to overcome these forces and loosen the molecules turning the solid into a liquid. a molecular solid has a low mpt.

Question 20

Molecular soft?

Answer 20

Soft - As the WIF’s between molecules in the molecular solid are weak the molecules can be separated which makes the solid soft.

Question 21

Molecular conductivity?

Answer 21

non - conductive conductivity requires moving charged particles. As a molecular solid is composed of molecules which do not have a charge, these solids do not conduct electricity.

Question 22

Molecular solubility?

Answer 22

Soluble - Polar molecular Substances generally dissolve in polar solvents eg water and non-polar Substances in non-polar Solvents eg hexane, for the same reason.
Soluble means the Solvent particles bond to the Solute particles, attracting them out of their solid lattice and Surrounding them in a hydration shell.