Chapter 13- Metals Flashcards
Define the term ‘paramagnetic’
It describes substances that are attracted into a magnetic field as a result of one or more unpaired electrons
Define the term ‘diamagnetic’
The quality of not being attracted to a magnetic field. Substances with no unpaired electrons are diamagnetic
Define the term ‘complex’
The combination of one or more anions/neutral molecules with a transition metal ion
Define the term ‘ligand’
A molecule/anion that can coordinate to a transition metal to form a complex
List some of the physical properties associated with metals.
Metals are mostly solid at room temperature.
Conductivity: thermal and electrical
Shine: metals can absorb and reemit light across a continuous band of energies.
Why are the elements towards the top right corner of the periodic table classed as nonmetals?
Electronegativity increases going from left to right; and going bottom to top. The elements in the top right corner of the periodic table hold onto their electrons too strongly to allow cations to be formed and stabilised.
How is the d-orbital count in transition metals in complexes worked out?
d-electron count = Group number – oxidation state
How do you assign oxidation states to transition metals in complexes?
Think about the charge needed on the metal to balance the charges on the ligands and the overall charge on the complex.
How are ligands bonded to the central metal ion in a metal complex?
They form dative covalent bonds with the metal ion
What characteristic do all ligands have in common?
All ligands are lone pair donors as they have lone pairs of electrons in the outer energy level. These are used to form co-ordinate bonds with the metal ion. In other words, all ligands function as Lewis bases
What are chelates?
A compound containing a ligand (typically organic) bonded to a central metal atom at two or more points.
Define the term ‘monodentate’
The term “monodentate” refers to ligands that bind to the metal through only one atom. Some examples of monodentate ligands are: chloride ions, water, hydroxide ions, and ammonia.
Define the term ‘bidentate’
Bidentate ligands have two donor atoms which allow them to bind to a central metal atom/ion at two points. Common examples of bidentate ligands are ethylenediamine, and the oxalate ion.
Define the term ‘polydentate’
Polydentate ligands range in the number of atoms used to bond to a central metal atom/ion. EDTA is an example of a polydentate ligand that has six donor atoms with electron pairs that can be used to bond to a central metal atom/ion.
Describe the chelate effect
The chelate effect is the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar nonchelating (monodentate) ligands for the same metal.
