1.3 Bonding Flashcards
What is ionic bonding
Strong electrostatic forces of attraction between oppositely charged ions held in lattice
Give an example of an ionically bonded substance
NaCl
How high are ionically bonded substances bp and mp? Why?
High as it takes lots of energy to break strong electrostatic forces of attraction between oppositely charged ions
Do ionic compounds conduct electricity? why?
Yes when molten/in solution as the ions are free to move and carry charge (don’t when solid)
What is simple molecular covalent bonding?
Strong covalent bonds between atoms, weak VDW forces of attraction between molecules
Are there any lone electrons in simple covalent bonding?
No - all involved in bonding
Can simple molecular covalent molecules conduct electricity? Why?
No all electrons used in bonding and aren’t free to move
Do simple molecular substances have a high/low mpt and bpt? Why?
Low- weak VDW forces of attraction between molecules that don’t take much energy to overcome (these are overcome rather than covalent bonds)
Describe macromolecular covalent bonding
Lattice of many atoms held together by strong covalent bonds
Do substances with macromolecular covalent bonds have high/low mpt and bpts? Why?
High, as it takes a lot of energy to overcome many strong covalent bonds
Do substances with macromolecular covalent bonds conduct electricity?
Most don’t as all electrons are used in bonding
Draw and describe structure of a diamond
3D tetrahedral structure of C atoms , with each C atom bonded to four others
Slide 26
Draw and describe structure of graphite
Similar to diamond - macromolecular covalent- but each C atom is only bonded to 3 others, so it is in layers
Weak VDW forces of attraction between layers mean they can slide over each other —> soft, slippery
One electron from each carbon is delocalised and can carry charge —> conducts electricity
Describe and draw metallic bonding
Lattice of positive metal ions strongly attracted to a sea of delocalised electrons.
Layers can slide over each other - malleable
Do metallic compounds have high/low bpt and mpts? Why?
High as strong forces of attraction between positive metal ions and negatively charged sea of delocalised electrons
Do metallic compounds conduct electricity? Why?
Yes as delocalised electrons can move throughout the metal to carry charge