Chemical Bonding and Structure Project by Brendan Reich

The Two Major Types of Chemical Bonds Ionic Bonding & Covalent Bonding

What’s an Ion? Ion Formation Cation Anion An electrically charged atom formed by the loss or gain of electrons. Formation Atoms either lose or gain electrons in order to completely fill their valance shell. In doing so they will either gain or lose electrons. This behavior of filling the valence shell is known as the octet rule. Cation An ion that has lost electrons and gained a positive charge. Anion An ion that has gained electrons and has a negative charge.

Ionic Bonding Ionic Compounds Ionic bonds are formed when electrons are transferred from one atom to another to form ions with complete outer shells of electrons. Cations and Anions are attracted to one another due to their opposite charge and gain a strong bond with one another. When Ions bond, the compound they form must end up with a charge of 0 (not including polyatomic ions). Ionic Compounds Ionic compounds consist of a metal and a nonmetal. Non-metals have high electronegativity and metals have low electronegativity. Ionic compounds, having such strong lattice, usually have high melting points because a large amount of energy is required to break their bonds. Because electrons are in a fixed position in bonds, they are unable to flow from atom to atom and ultimately don’t conduct electricity.

Covalent Bonding Occurs when one or more pairs of electrons are shared in order to have each atom involved fulfill the octet rule. Double bonds tend to be stronger than single bonds, and triple bonds tend to be stronger than double bonds. The electrons in any shared pair may originate from the same atom. Covalent Compounds Electrons do not flow well through covalent compounds well, so they aren’t great conductors of electricity and heat. Generally, covalent bonds have weaker lattices than ionic bonds, so they also have lower boiling and melting points. Covalent bonds are much more stable than ionic bonds.

Shapes of Simple Ions and Molecules The valence shell electron theory can help determine the shapes of simple molecules and ions. Pairs of electrons arrange themselves around the central atom so that they are as distant from each other as possible. To work out the shape of the actual molecule one must calculate the number of electrons round the central atom. In a molecule, double and triple bonds are considered to be a single pair of electrons, given that the electrons are located in the same domain. The are five basic shapes in which molecules may form.

Electron Domains Shape Name Bond angles 2 Linear 180° 3 Trigonal Planar 120° 4 Tetrahedral 109.5° 5 Trigonal Bypyramidal 90°, 120°, 180° 6 Octahedral 90°, 180°

Thank you