1.3 Bonding

• Ionic bonding involves charged ions held together by strong electrostatic attractions.
• In ionic bonding, sodium and chlorine each gain a full shell of electrons, forming sodium chloride.
• Sodium has an empty shell, which becomes stable by being attracted to chlorine.
• Group 1 elements form plus 1 ions, group 2 elements form plus 2 ions, and group 3 elements form plus 3 ions.
• Group 5 elements form 3 minus ions, group 6 form two minuses, and group 7 form one minus.
• Molecular ions include hydroxide, nitrate, ammonium, sulfate, and carbonate.
• The formula of an ionic compound can be worked out using the swap and drop method.
• In the swap and drop method, the charges are swapped over, the charges are dropped, and the subscripts are simplified.
• An example of using the swap and drop method is calcium ion and nitrate ion, which results in calcium nitrate.
• A molecule with five bond pairs and no lone pairs has a trigonal bi-pyramidal shape, as seen in PCL5.
• The electronegativity difference between two atoms in a covalent bond determines how polar the bond is.
• A molecule with three bond pairs and no lone pairs has a trigonal planar shape, as seen in BF3.
• Fluorine is the most electronegative element.
• A molecule with six bond pairs and no lone pairs has an octahedral shape, as seen in ClF3.
• The bigger the difference in electronegativity, the more polar the bond is.
• A molecule with bond pairs and no lone pairs has a linear shape, as seen in Beryllium dichloride (BeCl2).
• Electronegativity is the ability for an atom to attract electrons towards itself in a covalent bond, with the further up and right you go in the periodic table, the more electronegative the element.
• Another example of using the swap and drop method is calcium ion and oxygen, which results in calcium oxide.
• Every time a lone pair is added to a molecule, the remaining bond angle decreases by two and a half degrees.
• Water is based on a tetrahedral structure and has two bond pairs and two lone pairs.
• Diamonds can be cut to make gemstones.
• The shape of a molecule can be determined by the number of bond pairs and lone pairs of electrons.
• The bond angle in a tetrahedral structure is reduced by two and a half degrees for every lone pair added.
• The total number of bond pairs and lone pairs in a molecule determines its shape.
• If there are two lone pairs in a molecule, the bond angle shrinks even further.
• Graphite can conduct heat well because it is tightly packed and has strong covalent bonds.
• Graphite does not conduct electricity very well and does not have any free electrons, making it non-conductive.
• Graphite is insoluble because the bonds are too strong for water to break them apart.
• Diamonds are formed from volcanoes and can absorb and conduct heat.
• If there is a lone pair next to a bond pair, the repulsion between them is greater than if there were two bond pairs together.
• Sodium chloride, also known as salt, is an example of an ionic compound with a giant ionic structure.
• Sodium chloride dissolves in water due to the polarity of water, which can attract the positive and negative ions.
• Gases are very spaced out, have a random arrangement, low density, move around freely, and have a lot more energy than liquids and solids.
• Simple moleculars are covalent, can be liquids or gases, normally won't conduct electricity, and might be soluble depending on the polarity.
• Normal temperature ionic structures like sodium chloride have high melting points, are soluble, and conduct electricity.
• Normal temperature solids are generally insoluble, while metallic bonds are strong enough to break.
• Liquids are tightly packed, have a random arrangement, high density, move around freely, and are difficult to compress.
• Metallic bonding involves giant metallic lattice structures with positive net lines formed when metals donate electrons into the sea of delocalized electrons, and electrostatic attraction between the positive metal lines and delocalized electrons.
• Metals are good thermal conductors because they can transfer kinetic energy very easily, and are also good electrical conductors because they can carry a charge or current through the lattice.
• Giant covalent structures like graphite, diamond, silicon dioxide, and others are solids at normal temperature and don't conduct electricity.