Definitions
Define cation and anion
Cation: a species that is positively charged (has more protons than electrons)
Anion: a species that is negatively charged (has more electrons than protons)
Which atom forms a more positive ion?
Rb (rubidium) VS Ca (calcium)
Ca2+ is more positive that Rb+
During electrolysis, what happens at the anode and what happens at the cathode?
ANOX - anode oxidation
CARE - cathode reduction
What two factors affect the polarisation power of cations?
Size of the cation (smaller, stronger)
Charge of the cation (more positive, stronger)
What states of matter must ionic compounds be in to conduct electricity?
liquid (or aquaeous)
Define ionic bonding
electrostatic attractions between oppositely charged ions
Which atom has a bigger ionic radius and why?
F- VS Br-
Br- has more quantum shells
What would form if Cl- ions get oxidized during electrolysis?
2Cl-(aq) -> Cl2(g) + 2e-
Chlorine gas
What determines the strength of ionic bonds?
The size of the ions (smaller sizes, stronger bonds)
The charges of the ions (more difference in charge, stronger bonds)
What kind of structure do ionic compounds have?
Giant lattice
Define electrostatic attraction
a force of pull between oppositely charged particles
Which ion has a larger ionic radius and why?
Al3+ VS Na+
Al3+ because it has more protons
What are isoelectronic ions?
Ions of different elements that have the same electronic configuration
True or false: all ionic compounds have some degree of covalent bonding
True (due to polarisation)
Explain why ionic compounds are generally brittle?
Because their structure makes it easy for layers of ions to slide over each other (break)
Define polarisation
Uneven distribution of electrons in an anion due to the pull from cations in an ionic bond
Which cation has stronger polarising power?
Fr+ VS Sr2+
Sr2+ - smaller and more positive
An atom has the following electronic configuration:
1s22s22p63s23p4
What charge would the ion of this atom have?
2- (gains two electrons to become 1s22s22p63s23p6)
(this is a sulfur atom)
KF (because all halogens have the same charge, but F is the smallest)
True or false and explain why: LiF has a higher melting point than RbCl.
TRUE. Melting point is determined by the strength of ionic bonds and LiF has stronger electrostatic attractions than RbCl.
Define solubility (in terms of ionic compounds)
the degree to which ions are able to be dissolved in a solvent (typically water): related to the strength of water in breaking electrostatic attractions between ions
Which compound has a stronger ionic strength?
Mg3P2 VS Be3N2
Be3N2 - same charges, but smaller ions
Does a P3- ion have any unpaired electrons in its s- and p-orbitals?
No. All orbitals are filled.
If I make ionic compounds between Ca2+ and all halogens, which compound's anion would be the most polarised?
Explain how water is able to dissolve soluble ionic compounds.
Water is polar and can form electrostatic attractions with ions. If the force of attraction of water molecules is stronger that the internal electrostatic attractions between ions, it will separate ions and form hydration shells around them.