Can someone explain the molecular orbital theory and how to find the bond strength, bond length, and bond order? I'm also confused about the geometry of molecules & ions, like how to find the angles? (Like NH3 is 107 degrees, and H20 is 104.5 degrees, how do I find this when I'm given a certain molecule?)
The subjects in your post cover AT LEAST six or seven chapters in a freshman chemistry text and that is just an introduction. You have far too much waterfront to cover in one post.
dont you just use vsper theory to calculate the bond angles, find out the type of bond it is (tetrahedral etc) and go from there?
I think!
You are correct that VSEPR (Valence Shell Electron Pair Repulsion) theory can be used to predict the geometry of molecules and ions. VSEPR theory considers the repulsion between electron pairs to determine the arrangement of atoms in a molecule.
To determine the geometry of a molecule using VSEPR theory, you can follow these steps:
1. Draw the Lewis structure of the molecule, showing all the atoms and their connections using lines.
2. Count the total number of electron pairs around the central atom (including both bonding and nonbonding electron pairs).
3. Determine the electron pair arrangement by minimizing the repulsion between electron pairs. The possible arrangements include linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral, depending on the number of electron pairs.
4. Identify the molecular shape by considering only the atoms and ignoring the nonbonding electron pairs. For example, if there are four electron pairs around the central atom but two of them are nonbonding pairs, the molecular shape would be bent (angular).
As for your question about bond strength, bond length, and bond order, these can be explained within the framework of molecular orbital theory. Molecular orbital theory describes the behavior of electrons in molecules by using the concept of molecular orbitals, which are formed by the combination of atomic orbitals from the constituent atoms.
The bond strength, or the energy required to break a bond, can be estimated by the bond dissociation energy. This is the energy change associated with the breaking of a specific bond in a molecule. Higher bond dissociation energies generally indicate stronger bonds.
Bond length refers to the average distance between the nuclei of two bonded atoms. In general, shorter bond lengths correspond to stronger bonds. To determine bond length, experimental techniques such as X-ray diffraction or spectroscopic methods are commonly used.
Bond order represents the number of chemical bonds between two atoms. It can be calculated by subtracting the number of electrons in antibonding molecular orbitals from the number of electrons in bonding molecular orbitals and dividing the result by 2. A higher bond order indicates a stronger bond.
In summary, molecular orbital theory provides a framework for understanding bond strength, bond length, and bond order. VSEPR theory can be used to predict the geometry of molecules based on the electron pair repulsion.