CHEM2077: Group 12 - Zn, Cd, Hg Lecture Flashcards

VOCABULARY flashcards covering the classification, chemical properties, coordination geometry, organometallic chemistry, and toxicity of Group 12 elements based on CHEM2077 Lecture 10.

Transition Metal

An element that has an incomplete d-subshell in either its neutral atom or its common ions.

Group 12 Classification

Zinc (Zn), Cadmium (Cd), and Mercury (Hg) are not considered transition metals because they possess a full $d^{10}$ configuration in their ground state and all common oxidation states.

$$Hg_2^{2+}$$

The mercury(I) polycation which uniquely contains a metal-metal bond.

Relativistic Effects in Mercury

Effects that cause mercury's $6s$ electrons to be held very tightly to the nucleus, making them less available for metallic bonding and resulting in mercury being a liquid at room temperature.

Group 12 Color and Magnetism

Compounds of Group 12 are typically white/colorless and diamagnetic because no d-d electronic transitions are possible in a full $d^{10}$ shell.

Crystal Field Stabilization Energy (CFSE) in Group 12

Group 12 elements have no CFSE because they have a full d-shell, meaning coordination geometry is determined by VSEPR theory and ion size.

Mercury(II) Geometry

A coordination environment frequently adopted by Mercury(II) which is linear in nature.

Organozinc Reagents

Compounds such as $Et_2Zn$ used in the Simmons-Smith reaction; they are less reactive than Grignard reagents, offering better functional group tolerance.

Methylmercury ($MeHg^+$)

A notorious "soft" cation that binds strongly to sulfur in proteins and bioaccumulates up the seafood chain.

Itai-itai Disease

A condition characterized by brittle bones caused by Cadmium toxicity, where $Cd$ mimics Zinc in biological systems but fails to perform its catalytic functions.

Minamata Disease

Neurological damage, insanity, and paralysis caused by mercury poisoning, specifically from methylmercury.

Biomagnification

The process by which mercury undergoes an increase in concentration as it moves up the seafood chain, particularly in aquatic environments.