CAT(s) & Final EXam Review

CAT(s) & Final EXam Review



lattice energy (U or H_latt) - ANSWER-The energy required to change 1 mole of an
ionic compound to its gaseous ions


Compute the total spin: ↑↑↑↑↑↑ - ANSWER-n=6
S=nx1/2
=6x1/2
=3


Compute total spin: ↑↑↑↑↑↓ - ANSWER-2


Compute total spin: ↑↑↑↑↓↓ - ANSWER-1


Compute total spin: ↑↑↑↓↓↓ - ANSWER-0


Lewis dot notation of the Boron atom: - ANSWER-B surrounded by three dots


How are covalent bonds formed? - ANSWER-electron sharing


Polarity - ANSWER-Uneven distribution of electrons in molecules:

, example: HF


Aufbau's principle - ANSWER-Fill lower energy orbitals before higher energy
orbitals


Pauli exclusion principle - ANSWER-Paired electrons in an orbital should have
opposite spin


Below is lattice dissociation process
NaCl(s) ------> Na+(g) + Cl-(g) ΔH = +787 kJ/mol ----> this amount of energy is
required to break the ionic lattice


Na+(g) + Cl-(g) ------> NaCl(s) ΔH = -787kJ/mol


this amount of energy is released when Na+ and Cl- form solid NaCl


Factors affecting lattice energy - ANSWER-1. ionic charge
- the greater the charger the greater the electrostatic attraction hence the higher
the lattice energy: MgO has higher lattice energy compared to NaCl why?
2. Ionic radii (size)
- smaller ions, closer to the nucleus, stronger attraction due to less shielding
NaF>NaCl>NaBr>NaI


electron configuration of lead - ANSWER-Pb