AS Chemistry - Structure and Bonding

HideShow resource information
Why do ionic compounds have high melting and boiling Points?
- Ionic compounds have high melting and boiling points because - there are strong electrostatic forces of attraction between oppositely charged ions (ionic bonds). - A high amount of energy is needed to break these bonds.
1 of 20
What is the electrical conductivity of ionic compounds?
- Ionic compounds conduct when aqueous, (aq) or molten (l). - Ions are free to move and carry charge when molten or dissolved in waterThey do not conduct when solid, (s). - Ions are fixed in a lattice and cannot move.
2 of 20
What is the solubility of ionic compounds?
generally soluble in polar solvents, e.g. water. - insoluble in non-polar solvents e.g. hexane
3 of 20
Why are ionic compounds usually soluble in water?
- δ + H in water attracts negative ions in the ionic compound. - δ - O in water attracts positive ions in the ionic compound. - The water molecules pull the ions away from the lattice – the ions dissociate (compound dissolves).
4 of 20
Why do metals have high melting and boiling points?
Metals have high melting points because: - There are strong metallic bonds between positive metal ions and delocalised electrons. - A high amount of energy is needed to break these bonds.
5 of 20
Why do metals conduct electricity?
Metals conduct electricity because: - delocalised electrons are free to move and carry charge.
6 of 20
Solubility of metals?
Insoluble in any solvents (polar and non-polar).
7 of 20
Explain the physical properties of diamond in terms of its structure and bonding
giant covalent structure - hard and high melting point - There are strong covalent bonds between carbon atoms. - A high amount of energy is needed to break these bonds.
8 of 20
Explain the electrical conductivity of diamond
- Diamond cannot conduct electricity: - there are no free charge carriers - electrons are localised in covalent bonds
9 of 20
Solubility of diamond?
- Diamond is insoluble in any solvent (polar and non-polar). - Attractions between solvent molecules and carbon atoms will never be strong enough to overcome the strong covalent bonds in diamond
10 of 20
Why does graphite have a high melting point?
The melting point of graphite is high because: - there are strong covalent bonds between carbon atoms within layers so a large amount of energy is needed to break these bonds.
11 of 20
Explain the electrical conductivity of graphite
- Graphite conducts electricity - delocalised electrons are free to move along the layers and carry charge.
12 of 20
Solubility of graphite?
- Graphite is insoluble in any solvent (polar and non-polar). - Attractions between solvent molecules and carbon atoms will never be strong enough to overcome the strong covalent bonds in graphite
13 of 20
State the properties of graphene
Graphene is a pure form of carbon consisting of a one atom thick layer of carbon atoms. very strong for its low weight - good conductor of electricity (delocalised electrons carry charge) - good conductor of heat
14 of 20
Explain the physical properties of silicon, Si, in terms of its structure and bonding
giant covalent structure - hard and high melting point because large amount of energy required to break strong covalent bonds between Si atoms - does not conduct electricity because electrons are localised in covalent bonds
15 of 20
Why does iodine have a low melting point?
Iodine has a low melting point: - simple molecular - because little energy is needed to break the weak temporary induced dipole-dipole attractions between the molecules. In fact, iodine sublimes (solid → gas) on gentle heating at a low temperature be
16 of 20
Why doesn't Iodine conduct electricity?
Because there are no mobile ions or delocalised electrons
17 of 20
Solubility of iodine in polar solvents?
Partially Soluble (almost insoluble) Relatively strong hydrogen bonds between water molecules are too strong for simple structures to break Simple structures are unable to make hydrogen bonds with polar water molecules Solutions turns light brown I2(
18 of 20
Solubility of iodine in non polar solvents?
Soluble Weak van der Waal’s forces between nonpolar solvents are weak enough for simple structures to break Simple structures are able to make weak Van der Waals’ with non-polar solvents Solution turns purple I2(org)
19 of 20
Why is the boiling point of water higher than expected?
Hydrogen bonds are stronger than other types of intermolecular forces. - More energy is needed to break them
20 of 20

Other cards in this set

Card 2

Front

What is the electrical conductivity of ionic compounds?

Back

- Ionic compounds conduct when aqueous, (aq) or molten (l). - Ions are free to move and carry charge when molten or dissolved in waterThey do not conduct when solid, (s). - Ions are fixed in a lattice and cannot move.

Card 3

Front

What is the solubility of ionic compounds?

Back

Preview of the front of card 3

Card 4

Front

Why are ionic compounds usually soluble in water?

Back

Preview of the front of card 4

Card 5

Front

Why do metals have high melting and boiling points?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Structure and bonding resources »