Chapter 6: Thermochemistry. Chapter 7: Electronic Structure of Atoms. Chapter 8: Periodic Properties of the Elements.
Chapter 9: Chemical Bonding: Basic Concepts. Chapter Liquids, Solids, and Intermolecular Forces. Chapter Solutions and Colloids. Chapter Chemical Kinetics. Chapter Chemical Equilibrium. Chapter Acids and Bases. Chapter Thermodynamics.
Chapter Electrochemistry. Chapter Radioactivity and Nuclear Chemistry. Chapter Transition Metals and Coordination Complexes. Chapter Biochemistry. Full Table of Contents. This is a sample clip. Sign in or start your free trial.
JoVE Core Chemistry. Previous Video Next Video. Next Video Embed Share. Metal ions are always hydrated in aqueous solutions. Co-ordination number counts the number of bonds, not the number of ligands. This is the complex ion formed by attaching 3 ethanedioate oxalate ions to a chromium III ion. The shape is exactly the same as the previous nickel complex. The only real difference is the number of charges. Again, if you drew this in an exam, you would want to show all the atoms properly.
If you need to be able to do this, practice drawing it so that it looks clear and tidy! Refer back to the diagram of the ethanedioate ion further up the page to help you. The functional part of this is an iron II ion surrounded by a complicated molecule called haem heme. This is a sort of hollow ring of carbon and hydrogen atoms, at the centre of which are 4 nitrogen atoms with lone pairs on them. Haem is one of a group of similar compounds called porphyrins.
They all have the same sort of ring system, but with different groups attached to the outside of the ring. You aren't going to need to know the exact structure of the haem at this level.
Each of the lone pairs on the nitrogen can form a co-ordinate bond with the iron II ion - holding it at the centre of the complicated ring of atoms. The iron forms 4 co-ordinate bonds with the haem, but still has space to form two more - one above and one below the plane of the ring.
The protein globin attaches to one of these positions using a lone pair on one of the nitrogens in one of its amino acids. The interesting bit is the other position. Overall, the complex ion has a co-ordination number of 6 because the central metal ion is forming 6 co-ordinate bonds.
The water molecule which is bonded to the bottom position in the diagram is easily replaced by an oxygen molecule again via a lone pair on one of the oxygens in O 2 - and this is how oxygen gets carried around the blood by the haemoglobin. When the oxygen gets to where it is needed, it breaks away from the haemoglobin which returns to the lungs to get some more.
You probably know that carbon monoxide is poisonous because it reacts with haemoglobin. It bonds to the same site that would otherwise be used by the oxygen - but it forms a very stable complex.
The carbon monoxide doesn't break away again, and that makes that haemoglobin molecule useless for any further oxygen transfer. A hexadentate ligand has 6 lone pairs of electrons - all of which can form co-ordinate bonds with the same metal ion. The best example is EDTA. The diagram shows the structure of the ion with the important atoms and lone pairs picked out.
Note: The abbreviation EDTA comes from an old name for the parent acid of this - one where each of the negatively charged oxygens has a hydrogen atom attached. This used to be called e thylene d iamine t etra a cetic acid. Nobody ever calls it anything other than EDTA! The EDTA ion entirely wraps up a metal ion using all 6 of the positions that we have seen before. The co-ordination number is again 6 because of the 6 co-ordinate bonds being formed by the central metal ion. It is a Transition metal and located in Group 10 of the periodic table.
It has the symbol Pd. Rhodium Rh is a brittle silver-white metal that has the atomic number 45 in the periodic table. It is a Transition metal and located in Group 9 of the periodic table. It has the symbol Rh. Ruthenium Ru is a brittle silver-gray metal that has the atomic number 44 in the periodic table.
It is a Transition metal and located in Group 8 of the periodic table. It has the symbol Ru. Technetium Tc is a silvery-gray metal that has the atomic number 43 in the periodic table. It is a Transition metal and located in Group 7 of the periodic table. It has the symbol Tc. Molybdenum Mo is a silvery-white metal that has the atomic number 42 in the periodic table.
It is a Transition metal and located in Group 6 of the periodic table. It has the symbol Mb. Niobium Nb is a shiny white metal that has the atomic number 41 in the periodic table. It is a Transition metal and located in Group 5 of the periodic table. It has the symbol Nb. Zirconium Zr is a gray white metal that has the atomic number 40 in the periodic table. It is a Transition metal and located in Group 4 of the periodic table.
It has the symbol Zr. Yttrium Y is a silvery metal that has the atomic number 39 in the periodic table. It is a Transition metal and located in Group 3 of the periodic table. It has the symbol Y. Transition metals are the central section of the periodic table containing the majority of the metals.
Also have d sub orbitals producing certain chemical properties. A complex is the term given to a central metal ion that is surrounded by atoms that are able to donate lone pairs of electrons to form bonds to the central metal ion. The central metal ion is the metal ion at the centre of a complex usually with a positive charge and a transition metal element.
The electron is the smallest sub atomic particle that make up the atom. Has a negative charge and is located in shells that orbit the nucleus. A lone pair is a pair of electrons on an atom that are not involved in bonding. A ligand is a molecule or atom that can form a bond with a central metal ion, usually by donating a lone pair of electrons to form a coordinated bond. A multidentate ligand can form when more than 2 bonds with a central metal ion by donating more than one pair of electrons i.
This number determines the geometry, shape and other chemical properties of the complex. The bond angle is a measure of the angle between two bonds that is changed depending on the repulsion between lone pairs and bonded pairs helps to determine the shape of covalent compounds. Table of Contents.
Atomic Structure. Element Names and Symbols. Elements in Everyday Life. Groups and Periods. Metals and Non Metals. Elements, Compounds and Mixtures. States of Matter. State Changes. Physical Properties. Chemical Properties. Atomic Number. Atomic Mass.
Why is it Important? Who Uses It? Why Gaps? All Elements Abundant? Elements Made in Lab? History of Alchemy. Modern Day Alchemy. Alchemy Symbols. Ancient Greek Symbols. The Three Primes. Alchemy Symbols of Compounds. Atoms, Elements, Molecules, Compounds. Metallic Bonding. Covalent Bonding. Intermolecular forces. Simple Covalent. Giant Covalent. Ionic Bonding. Ionic Properties. Solids, Liquids, and Gases. Exceptions to States. Atomic Radius. Nuclear Charge. Ionisation Energies.
Oxidation States. Radioactivity and Decay. Groups and Patterns. Alkaline Metal: Group 1. Alkaline Earth Metals: Group 2. Transition Metals. A ligand is a species which can use its lone pair of electrons to form a dative covalent bond with a transition metal. Cations of d-block metals transition metals are small, have a high charge, and have available empty 3d and 4s orbitals of low energy.
They form complex ions readily when their partially filled d subshell accepts donated electron pairs from other ions or molecules. The number of lone pairs of electrons a cation can accept is known as the coordination number of the cation.
This number depends on the size and electronic configuration of that cation and on the size and charge of the ligand. Six is the most common coordination number, although 4 and 2 are also known. Note that the formula of the ion is always written inside square brackets with the overall charge written outside the brackets. When two reactants are mixed, the reaction typically does not go to completion. Rather, the reaction will form products until a state is reached in which the concentrations of the reactants and products remain constant.
At this point, the rate of formation of the products is equal to the rate of formation of the reactants. The reactants and products are in chemical equilibrium and will remain in this state until affected by some external force.
The equilibrium constant K c for the reaction relates the concentration of the reactants and products. For example, here is the reaction between the iron III ion and thiocyanate ion:.
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