Chapter 8 Covalent Bonds

Use electronegativitie values to determine if a bond is ionic, polar covalent, nonpolar covalent

0.0 - 0.4 Nonpolar Covalent : H-H (0.0) 0.5 - 1.0 Moderately polar covalent 1.0 - 1.7 Very polar covalent ≥ 1.8 Ionic Na-Cl (2.1)

Explain how a molecule may contain a polar bond, but the entire molecule may still be nonpolar

A bond dipole occurs when there is a separation of positive and negative charges in a bond. Together, the positive "pole" and the negative "pole" make a dipole. Ex: C=O bonds are both polar, with oxygen pulling electrons away from carbon. But they are pulling equally in opposite directions. The two bond dipoles cancel. As a result, the molecule is nonpolar.

Describe how electronegativity values determine the distribution of charge in a polar molecule

A polar covalent bond, known also as a polar bond, is a covalent bond between atoms in which the electrons are shared unequally. The more electronegative atom attracts electrons more strongly and gains a slightly negative charge. The less electronegative atom has a slightly positive charge.

Describe the information a molecular formula provides

Chemical formula of a molecular compound Shows how many atoms of each element a molecule contains Ex: NH3 Does not indicate molecule's structure Not always in the smallest whole-number ratio of atoms Ethane - C2H6 not CH3

Describe how atoms form double or triple covalent bonds

Covalent bonding occurs when electrons are shared between atoms. Double and triple covalent bonds occur when four or six electrons are shared between two atoms, and they are indicated in Lewis structures by drawing two or three lines connecting one atom to another.

Compare and contrast ionic and covalent bonds (name of compound, strength of bonds, what happens to electrons, conductivity, solubility, types of elements involved)

Ionic compounds are formed from strong electrostatic interactions between ions, which result in higher melting points and electrical conductivity compared to covalent compounds. Covalent compounds have bonds where electrons are shared between atoms. Due to the sharing of electrons, they exhibit characteristic physical properties that include lower melting points and electrical conductivity compared to ionic compounds.

Distinguish between the melting points and boiling points of molecular compounds and ionic compounds

Molecular Compounds- low melting and boiling points Ionic Compounds- high melting and boiling points

Describe how VSPER Theory helps predict the shapes of molecules- draw common shapes- linear, bent, trigonal pyramidal, tetrahedral (may use models)

based off the VSPER theory, the pairs of valence electrons are arranged as far apart from each other as possible, meaning that the unshared pairs are repulsed as far as possible

Describe how electrons are shared to form covalent bonds

electrons sharing occurs so that atoms attain the electron configuration of noble games, combinations of atoms of the nonmetals and metalloids in Groups 4A, 5A, 6A, & 7A form covalent bonds

Demonstrate how Electron Dot structures represent shared electrons

ex: oxygen

Evaluate the strength of intermolecular attractions compared with the strength of ionic and covalent bonds

intermolecular attractions are weaker than either ionic or covalent bonds