F-Block Flashcards Preview

Core 8 > F-Block > Flashcards

Flashcards in F-Block Deck (17)
Loading flashcards...
1

F-Orbitals

4f
n = 4. l = 3
ml = -3, -2, -1, 0, 1, 2, 3
ms = +1/2, -1/2
degeneracy 2l+1 = 7
nodes n -1 = 3
radial n - l - 1 = 0

2

Radial Distribution Function Ln

no radial nodes
4f close to nucleus, probability of electrons close to the nucleus
poor shielding
core-like electrons
poor overlap with ligands
ionic bonding

3

Radial Distribution Function Ac

one radial node
probability further from nucleus
less core-like
more expansive
better overlap with ligands
covalent bonding

4

Down a Group

increased size
decreased ionisation energies

5

Across a Period

decreased size
increased ionisation energies
increased Zeff

6

4f and 5f Trends

radii drastically decrease across a period
Ln/Ac contraction
poor screening of f-electrons
4f feels increased nuclear charge

7

Relativistic Effect

electrons moving in vicinity of highly charged nucleus
approach speed of light
velocity increases so does J and mass

8

Spectroscopic Properties

weak narrow bands
forbidden f-f transitions
no crystal field effect

9

Coordinating Ln

ionic bonding
hard donor ligands needed N/O/F
high coordination number
large ionic radii
strong chelate/macrocyclic effects entropy increased on displacing water for multidentate ligands

10

NMR Shift Reagents

Ln3+ coordinated to Lewis base
separate race if mixture into enantiomers
determine e value
paramagnetic - induces change in chemical shift

11

MRI Contrast Agent

contrast between H and H2O I'm healthy and diseased tissues
cancerous tissues - longer relaxation time
Gd- low toxicity when chelated, high magnetic moment, soluble

12

Ln Probes

Ln3+ similar size to Ca2+
substitute in biological systems
luminescence

13

Coordinating Ac

not highly available
radioactive
toxic
U and Th
RN2-

14

Ac in Nuclear Fuel

rods dissolved in HNO3
separation of U and Pu on stability
processed to AnO2

15

Alkyl

prone to nucelophilic attack
kinetic ally unstable unless with bulky ligands
agostic interactions hard to detect - paramagnetic

16

Ln

+3 oxidation state
+2 with kinetic control
small, hard ligands
ionic
sharp spectra
low absorption coefficient

17

Ac

+3 oxidation state
covalent
high absorption coefficient