Question

What are the three basic types of solids and the composite units of each? What types of forces hold each type of solid together?

Answer 1

The 3 basic mechanism used to hold solid state are Bonding, Intermolecular Forces, and Electron Sea, or the Metallic Bond.

:  Solids composed of discrete molecules are kept that way because of van der Waals forces. The term van der Waals forces refers to the entire collection of intermolecular forces which include hydrogen bonding, dipole-dipole attraction and London dispersion forces. All molecules experience London dispersion forces. In addition, polar molecules can also include dipole-dipole interactions. And if hydrogen is bonded internally to N, O or F, then hydrogen bonding can also be exhibited.

In the case of paraffin wax, only London dispersion forces are in evidence. In water ice we have all three van der Waals forces: London dispersion forces which are always present, dipole-dipole attraction since water is polar, and hydrogen bonding since H is internally bonded to oxygen.

Keep in mind that hydrogen bonding is a form of weak, intermolecular covalent bonding in which H forms a bridge between molecules. Hydrogen bonding is not just electrostatic attraction or a type of "super" dipole-dipole attraction.

============== Follow up ================

Shaundra means well, but ... First of all, all molecules are neutral, but in a compound with a permanent dipole moment there is a charge distribution so that one end exhibits a slight + charge and one end exhibits a slight - charge. It is these oppositely charged ends that attract other polar molecules.

There is more to hydrogen bonding that simply having a positive end and negative end. Chemists have known for some time that the hydrogen bond has distinct covalent bond characteristics and that hydrogen bonding is not merely a type of electrostatic attraction. Recently the IUPAC redefined the hydrogen bond. Read more here:http://media.iupac.org/reports/provision... and look at line 79 in particular.

London dispersion forces are the result of temporary dipoles and are always found between discrete molecules, even if other intermolecular forces are also present. Metallic bonds are found between atoms of metals. Metallic bonds are a type of covalent bonding in which the electrons are highly delocalized, and can move easily from atom to atom. Metallic bonding is not found in discrete molecules.