Tutor profile: Thomas K.
Subject: Organic Chemistry
Why is orbital hybridization so important?
Orbital hybridization forms the cornerstone of all organic reactivity. By hybridizing their base s and p orbitals into various combinations; the most popular of which are sp3, sp2, and sp; atoms are able to create better orbital overlap with other species with which they are reacting. This facilitates the association of electrons with the new chemical species and the formation of new bonds. Additionally, orbital hybridization has a significant impact on the electronic energy of atoms and molecules - there are many situations in which hybridization to sp3 can optimize the angles and bond distances in a compound by invoking the principles of the VSEPR model to induce a tetrahedral molecular geometry. Orbital hybridization allows molecules to exist in optimal energy states and is one of the most significant factors in chemical reactivity.
How do we know what molecules look like?
We can visualize molecules using a variety of spectroscopic techniques. In other words, we examine how molecules interact with light in order to determine their physical properties at the micro scale. The appropriate spectroscopic techniques differ based on the type of chemistry you are doing. For instance, nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy are generally used in organic and biochemistry, while Raman spectroscopy and ultraviolet-visible (UV-vis) spectroscopy are generally used in physical chemistry. Mass spectrometry is another incredibly useful tool in all areas of chemistry, but especially in analytical chemistry, however this is not a spectroscopic technique. Finally, X-ray crystallography is very valuable for getting an exact image of what a pure, solid compound looks like. All of these spectroscopic techniques yield spectra that can be learned to be interpreted very quickly!
Subject: Basic Chemistry
What are atoms made up of?
Atoms are composed of three subatomic particles: protons, neutrons, and electrons. Protons and neutrons are the larger subatomic particles that contribute to the atomic mass and comprise the atomic nucleus. Protons are positively charged, while neutrons are electronically neutral. Atoms, however, are neutral (unless they are ionized, of course), meaning that there needs to be some negative charge in the mix as well. This is where the electrons come in - to balance out the positive charge of the nucleus, there is an equal number of negatively-charged electrons to the number of protons to make the atom electronically neutral. Electrons are very small and are generally regarded as mass-less, and they orbit around the nucleus. These characteristics make them relatively easy to move around between different atoms in chemical reactions.
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