CHM 2046 Chapter Notes - Chapter 22: Amphoterism, Zirconium, Covalent Bond

• School: University of Florida
• Department: Chemistry
• Course: CHM 2046
• Professor: Christou

Document Summary

4: partially filled d shell gives colored species, partially filled d shell often results in unpaired electrons, size of mn+ ions down a group: 3d < 4d 5d (due to an effect called the lanthanide contraction), size of mn+ across a period (l to r): decreases at first, then remains fairly constant, electronegativity down a group: 3d > 4d < 5d. = less common or rare oxidation states. Trends in bonding: higher oxidation states give more covalent bonding (to reduce high charge to size ratio i. e. high charge density). Chromium(iii) oxide (cr 2o 3 i. e. cr 3+): amphoteric (i. e. similar to al2o3) can act as an acid: or as a base: Chromium(vi) oxide (cro 3 i. e. cr 6+): is covalent and acidic. + to n2 (g) i. e. nitrogen( iii) oxidized to e. g. decomposition of the ammonium dichromate salt (nh4)2cr2o7 (s) cr2o3 (s) + n2 (g) + 4h2o half reactions: 2 cr6+ + 6 e 2 cr3+