Bonding Flashcards
how are the ions are held together in solid sodium metal.
Strong attractions between positive ions (1)
and delocalised electrons (1)
how are the ions are held together in solid sodium chloride.
Many strong electrostatic attractions (1)
between oppositely charged ions (1)
The melting point of sodium chloride is much higher than that of sodium metal.
What can be deduced from this information?
the ionic bonding in NaCl is stronger and so requires more energy (1)
to break than the metallic bonding in Na (1)
Compare the electrical conductivity of solid sodium metal with that of solid sodium
chloride and say why this is (3)
Comparison:
Sodium conducts and sodium chloride does NOT conduct (1)
Explanation:
(Delocalised) electrons flow though the metal (1)
Ions can’t move in solid sodium
why is sodium metal malleable
Layers can slide over each other (1)
Explain why the bond angle in an amide ion is smaller than that in an ammonia
molecule.
More lone pairs on NH2 than on NH3 (1)
Lone pairs repel more than bonding pairs (1)
Describe the bonding that is present in metals.
strong electrostatic attraction (1)
between postive ions (1)
and delocalised electrons (1)
why is aluminium a better conductor of electricity than magnesium
more outer shell electrons (1)
in aluminium than in magnesium so there is a stronger attraction (1)
between delocalised electrons and ion per ion of Al3+ than in Mg2+ (1)
why is the O–H bond in a methanol molecule is polar.
Oxygen is more electronegative than hydrogen (1)
which causes H&+ and O&- (partial charge) (1)
in terms of the intermolecular forces, why is the boiling point of methanol is much higher than that of oxygen.
van der Waals’ forces between oxygen molecules (1)
Hydrogen bonding between methanol molecules (1)
H-Bonding stronger than van der Waals (1)
Explain how the bonding and structure lead to the typical metallic properties of electrical conductivity and malleability.
conductivity:
electrons can flow within the structure (1)
electrons carry charge (1)
malleability:
positive ions in the lattice are all the same size (1)
so layers of ions can slide over each other easily (1)
Suggest a reason why aluminium is a better conductor of electricity than magnesium.
more delocalised electrons (1)
in aluminium compared with magnesium (1)
Define the term electronegativity.
the power of an atom to withdraw electron density from a covalent bond
Explain how the strongest type of intermolecular force in liquid HF arises.
- large difference in electronegativity between H and F
- δ+H-Fδ- dipole created
- attraction between δ+H and lone pair on F
Explain the increaese in the boiling points of the hydrogen halides from HCl to HI.
Increase in number of electrons
so stronger Van Der Waals forces between molecules
which requires more energy to break
