1. Unit 7: Covalent Bonding
covalent bond: formed by sharing e–’s between atoms. (nonmetals only)
molecular compound: neutral group of atoms joined by covalent bonds.
Some compounds are so different from ionic compounds that attractions between ions fail to explain their bonding.

2. Ionic Bonds transfer electrons between a metal and non-metals (usually). Covalent Bonds share electrons between non-metals. Idea is still to get a full valence shell “8 electrons…” around each atom. Whether it’s covalent or ionic is dictated by the difference in the atom’s electronegativities.

3. diatomic molecules (all covalently bonded):
two atoms of the same element.
There are Seven Diatomic Molecules Hydrogen (Gas) Nitrogen (Gas) Oxygen (Gas) Fluorine (Gas) Chlorine (Gas) *YOU MUST KNOW THESE. FROM NOW Bromine (Liquid) ON THE NAME MEANS THE MOLECULE Iodine (Solid)

4. molecular formula:
shows how many atoms of each element

5. Properties of molecular compounds:
lower m.p.’s than ionic compounds.
(usually liquid or gas at room Temp.)
poor conductors

7. 1. A molecular compound usually consists of
Quick Quiz!
1. A molecular compound usually consists of
two metal atoms and a nonmetal atom.
two nonmetal atoms and a metal atom.
two or more metal atoms.
two or more nonmetal atoms.

8. 2. A molecular formula shows…
Quick Quiz.
2. A molecular formula shows…
how many atoms of each element a molecule contains.
a molecule's structure.
which atoms are bonded together.
how atoms are arranged in space.

9. low conductivity and high melting points.
Quick Quiz.
3. Compared to ionic compounds, molecular compounds tend to have relatively
low melting points.
high melting points.
high conductivity.
low conductivity and high melting points.