Paper 2 Flashcards
1
Q
calcium: atomic vs ionic radius
A
- less shielding
- greater effective nuclear attraction (due to higher rate of protons to electrons, because two electrons have been lost)
2
Q
when mentioning ionic bonds
A
define them
3
Q
don’t just say particles
A
what are they?
4
Q
differing electrical conductivities
A
differences in ionic radius
5
Q
hydrogen atoms held together
A
the attraction between the shared bonding pair of electrons between the nuclei
6
Q
when drawing the electrons in a molecule of ethene
A
you need not use triangles
7
Q
when drawing an ammonium ion
A
dative covalent bond
8
Q
why does pure silicon have low conductivity?
A
- silicon outer electrons asre fixed in covalent bonding
- the electrons are not delocalised; they cannot move
9
Q
rather than saying an electron imbalance, say
A
‘an uneven distribution of electrons’
10
Q
6 marker
A
- 2-methylpentane is an organic molecule with intermolecular forces: London forces, but no dipole-dipole attractions or hydrogen bonding
- it is insoluble in water, because it is not polar, whereas water is polar.
- water contains hydrogen bonds - the formation of London forces between the alkane and the water would not energetically compensate
- it is soluble in hexane because hexane is an organic solvent with the same intermolecular forces - energetically feasible because the breaking of London forces forms new London forces
- potassium bromide is an ionic compound - giant ionic lattice with ions joined by ionic bonds (electrostatic attraction between oppositely charged ions)
- it is soluble in water because when the ions dissociate they are charged, attracted to the polarity of water (hydrogen to anions, oxygen to cations)
- it is insoluble in hexane because breaking the ionic bonds would not be energetically compensated for
11
Q
why does HF have a higher BP than HCl?
A
- fluorine is more electronegative than chlorine
- can form hydrogen bonds
- strongest intermolecular force
- requires more energy to overcome
12
Q
greater London forces
A
caused by greater number of electrons, more energy needed to overcome them
