16Jul 2016 by Vincent Summers 3 Comments

The Bent Water Molecule – Why Is It Bent?

Chemistry, Physics
[caption id="attachment_14934" align="alignright" width="480"] Liquid Water (Left) - Ice (Right)[/caption] The water molecule, H₂O, consists of two hydrogen atoms and one oxygen atom. A naïve attempt at writing its structure out in full is H‒O‒H. What’s naïve about this? This drawing is linear—a straight line. It is naïve because the water molecule is a bent water molecule... bent at about 104.5°. It is a good thing for us that this is so, since this imparts a degree of polarity to the water molecule. Polarity, in turn, gives rise to hydrogen bonding. The hydrogen bonding of molecules assures water’s liquidity. In addition hydrogen bonding influences water’s crystallization, so that ice is lighter than very cold water. Ice thus floats, forming an insulating blanket atop lakes and other bodies of water. This…
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10Nov 2014 by Vincent Summers No Comments

What Are Hybrid Atomic Orbitals?

Chemistry
[caption id="attachment_6346" align="alignright" width="440"] Pre-hybridization 1s, 2s, 2px, 2py, and 2pz atomic orbitals.[/caption] An atom consists of two components - a nucleus and its orbiting electrons. Nuclei contain neutrons and protons bound together by nuclear force. Electrons travel in well-defined atomic orbitals outside the nucleus. Orbitals come in different shapes. They contain up to two electrons each. A collection of orbits forms an electron shell. Atoms can have more than one shell. Orbitals and shells are identified by letters and numbers. The details are beyond the scope of this article; however, atoms begin filling electron orbitals in the order, Orbitals: s, p, d, f... Shells: 1, 2, 3, 4... First Elements Thus the first ten elements fill their orbitals and shells, Hydrogen 1s¹ Helium 1s² Lithium 1s² 2s¹ Beryllium 1s²…
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19Mar 2014 by Vincent Summers No Comments

Drawing Single Bond Organic Hydrocarbons

Chemistry
[caption id="attachment_5904" align="alignright" width="440"] Straight Chain Pentane[/caption] Carbon is one of the few elements that readily bonds to itself, thus allowing the formation of macromolecular structures. It is not at all an uncommon thing to see a lengthy carbon-based structure, possessing molecular weight well up into the tens of thousands. Compare this with an “ordinary” molecule such as table salt, sodium chloride (NaCl) with its molecular weight—a mere 58. Drawing Single Bonded Organic Structures Ordinarily, carbon compounds are written by chemists in as simple a form as possible. Thus, drawing single bond organic hydrocarbons such as n-hexane, we write, C₆H₁₄ or, a little more in detail, CH₃(CH₂)₄CH₃ or, perhaps even, CH₃‒CH₂‒CH₂‒CH₂‒CH₂‒CH₃ [sc name="MidArticleAdsense"] Need Greater Specificity? The problem is, carbon single bonds possess tetrahedral symmetry. This means that single bonds…
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28Oct 2013 by Vincent Summers No Comments

Silicon Tetrachloride Acts Like a Strongly Electronegative Atom

Chemistry
[caption id="attachment_5121" align="alignright" width="440"] Silicon Tetrachloride Molecule[/caption] The empirical formula of the compound silicon tetrachloride is SiCl₄. The molecule possesses tetrahedral symmetry. This means the atom of silicon is located at the center and the four atoms of chlorine are located at the four corners of a tetrahedron. Each chlorine atom is strongly electronegative, so the molecule of SiCl₄ strongly draws electrons. The core, silicon atom is insignificantly electronegative. Elemental Electronegativity Electronegativity is the tendency of an atom or other particle to attract electrons. It is high when an atom is small and outer electrons are least shielded from the positive nucleus. This makes fluorine the most electronegative of elements. Conversely, the alkali metal astatine, is least electronegative. Chlorine, while not so much so as fluorine, is still very electronegative.…
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