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This article explores ionic and covalent bonding, the fundamental forces that shape chemical compounds. Ionic bonds form between metals and non-metals through the transfer of electrons, resulting in charged ions, or cations and anions, that attract each other. Ionic compounds are typically crystalline with high melting points and are soluble in water. Conversely, covalent bonds involve the sharing of electrons, forming molecules with varying bond types, such as single, double, and triple bonds, featuring distinct properties. This comprehensive guide highlights their implications in technology, such as superconductors.
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Bonding Periodic Table Stuff & Redox
Ionic Bonds (Salts) • Between a metal (usually) and a non-metal (usually). The metal gives up its electron to the non-metal. Giving up electrons turns the metal into a positively charged ion called a cation. Gaining the electrons turns the non-metal into a negtatively charged ion called an anion. • The positive and negative charges attract each other. This is the ionic bond. • Ionic compounds are crystals – the formula shows the ratio of the elements in the compound. It is known as a formula unit. • They have high melting points. • They are more likely to be soluble in water, the universal solvent. • They are electrolytes.
CaF2 CsCl
Experienced chemists can often predict the structure that a given ionic species will adopt, based on the nature of the ions involved. This means that it is often possible to design ionic compounds having certain well-defined and desirable properties. As an example, chemists have been able to make high-temperature superconductors, such as the complicated ionic compound, YBa2Cu3O4. This solid conducts electricity with no resistance at all at low temperature (below ca. -100 degrees centigrade). Previous superconductors only had this property at much lower temperatures. The lack of resistance makes superconductors very useful in a number of technological applications - e.g. in designing high-speed trains that levitate above the track! The repeating structure of this solid is shown below (oxygen is large and red, barium large and yellow-ish, yttrium small and pink, and copper small and blue). Notice how many oxygen ions surround each barium and yttrium ion.
Covalent Bonds (Not-Salts) • The electrons are shared between compounds. This allows each atom to have a full outer shell for stability. • Covalent compounds are represented by true molecules. The formula represents how many of each atom there are in the molecule. • 1 electron each shared is a single bond, 2 electrons each is a double bond and 3 electrons each is a triple bond. • They have low melting points. • They don’t usually dissolve well in water. • They are not electrolytes.
Bonding in Covalent Compounds Plot of region where e- sit. Not localized.
Bonding between Molecules – Intermolecular Bonding: Hydrogen Bonding
Bonding between Molecules – Intermolecular Bonding: Dipole - Dipole Bonding & Induced Dipole Bonding (london dispersion) Collectively: van der waals forces http://chemsite.lsrhs.net/bonding/LondonDispersion.html
Families/Groups; Periodic Law; Ionization energy & Electronegativity
Assigning Oxidation Numbers: PO4-3 H2SO4