It also explains the bonding in a number of other molecules, such as violations of the octet rule and more molecules with more complicated bonding (beyond the scope of this text) that are difficult to describe with Lewis structures. Molecular orbital theory (MO theory) provides an explanation of chemical bonding that accounts for the paramagnetism of the oxygen molecule. You can see videos of diamagnetic floating frogs, strawberries, and more. If you place a frog near a sufficiently large magnet, it will levitate. Living things contain a large percentage of water, so they demonstrate diamagnetic behavior. Water, like most molecules, contains all paired electrons. We can calculate the number of unpaired electrons based on the increase in weight. When we compare the weight of a sample to the weight measured in a magnetic field ( ), paramagnetic samples that are attracted to the magnet will appear heavier because of the force exerted by the magnetic field. Magnetic susceptibility measures the force experienced by a substance in a magnetic field. And yet, the Lewis structure of O 2 indicates that all electrons are paired. Such attraction to a magnetic field is called paramagnetism, and it arises in molecules that have unpaired electrons. Thus, when we pour liquid oxygen past a strong magnet, it collects between the poles of the magnet and defies gravity, as in. By itself, O 2 is not magnetic, but it is attracted to magnetic fields. However, this picture is at odds with the magnetic behavior of oxygen. There is an O=O double bond, and each oxygen atom has eight electrons around it.
This electronic structure adheres to all the rules governing Lewis theory. We would write the following Lewis structure for O 2: However, one of the most important molecules we know, the oxygen molecule O 2, presents a problem with respect to its Lewis structure. Relate these electron configurations to the molecules’ stabilities and magnetic propertiesįor almost every covalent molecule that exists, we can now draw the Lewis structure, predict the electron-pair geometry, predict the molecular geometry, and come close to predicting bond angles.Write molecular electron configurations for first- and second-row diatomic molecules.Calculate bond orders based on molecular electron configurations.Describe traits of bonding and antibonding molecular orbitals.Outline the basic quantum-mechanical approach to deriving molecular orbitals from atomic orbitals.Spectroscopic and Magnetic Properties of Coordination CompoundsĪldehydes, Ketones, Carboxylic Acids, and Estersīy the end of this section, you will be able to: Occurrence, Preparation, and Properties of Transition Metals and Their CompoundsĬoordination Chemistry of Transition Metals Transition Metals and Coordination Chemistry Occurrence, Preparation, and Properties of the Noble Gases Occurrence, Preparation, and Properties of Halogens Occurrence, Preparation, and Properties of Sulfur Occurrence, Preparation, and Compounds of Oxygen Occurrence, Preparation, and Properties of Phosphorus Occurrence, Preparation, and Properties of Nitrogen Occurrence, Preparation, and Properties of Carbonates Occurrence, Preparation, and Compounds of Hydrogen Structure and General Properties of the Nonmetals Structure and General Properties of the Metalloids Occurrence and Preparation of the Representative Metals Representative Metals, Metalloids, and Nonmetals The Second and Third Laws of Thermodynamics Shifting Equilibria: Le Châtelier’s Principle Stoichiometry of Gaseous Substances, Mixtures, and Reactions Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law Periodic Variations in Element Properties Mathematical Treatment of Measurement Resultsĭetermining Empirical and Molecular FormulasĮlectronic Structure and Periodic Properties of ElementsĮlectronic Structure of Atoms (Electron Configurations) Measurement Uncertainty, Accuracy, and Precision
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