ch. 8.4

nonpolar covalent bond

covalent bond where electrons are shared equally

polar covalent bond

a covalent bond in which electrons are not shared equally

polar bond

a covalent bond in which electrons are shared unequally

polar molecule

a molecule in which the charges are unevenly distributed

dipole

a molecule or a part of a molecule that contains both positively and negatively charged regions

van der waals forces

a slight attraction that develops between the oppositely charged regions of nearby molecules

dipole interactions

intermolecular forces resulting from the attraction of oppositely charged region of polar molecules

dispersion forces

weak forces that result from temporary shifts in the density of electrons in electron clouds

network solids

solids in which all of the atoms are covalently bonded to each other

hydrogen bonds

very weak bonds; occurs when a hydrogen atom in one molecule is attracted to the electrostatic atom in another molecule

How do electronegativity values determine the charge distribution in a polar covalent bond?

the more electronegative atom attracts electrons more strongly and gains a slightly negative charge. The less electronegative atom has a slightly positive charge.

What happens when polar molecules are between oppositely charged metal plates?

When polar molecules are placed between oppositely charged plates, they tend to become oriented with respect o the positive and negative plates

Compare the strengths of intermolecular attractions to the strengths of ionic bonds and covalent bonds.

intermolecular attractons are weaker than either ionic or covalent bonds

Explain why network solids have high melting points

Melting a network solid would require breaking covalent bonds throughout the solid

How does a network solid differ from most other covalent compounds?

Covalent compounds exist as molecules made of two or more atoms joined together. The atoms share electrons between them in a stable chemical (covalent) bond.