Aim: What are molecular compounds?

DO NOW: 1. COMPARE AND CONTRAST METALLIC BONDING AND IONIC

BONDING.

2. WHAT WOULD BE THE IONIC CHARGE FOR AN ATOM WITH THIS LEWIS DOT STRUCTURE?

X Y

Ionic Compounds Review

In Ionic Bonding electrons are being transferred (“given up” or “stolen away”)

Occurs between a metal and a nonmetal resulting in the formation of a salt

Molecular Compounds

The atoms in molecular compounds are held together by covalent bonds

Covalent bonds are the sharing of electrons between nonmetals.

Molecule

A molecule is a neutral group of atoms joined together by covalent bonds

Diatomic molecules- two atoms, either of the same or different element) are joined together by a covalent bondEx: H2, O2, N2, Cl2, Br2, I2, F2

HCl

Salt vs Molecules

A salt is a metal cation and a nonmetal anion joined together by an ionic bond

A molecule is a group of atoms joined together by a covalent bond

A compound is a group of two or more elements bonded together (ionic or covalent)

Covalent Bond vs Ionic Bond

Properties of Molecular Compounds

Mostly liquid or gases at room temperatureLower melting points than ionic compounds (meaning

the bonds are weaker than ionic bonds)

Molecular Formulas

The molecular formula is the formula of a molecular compound

It shows how many atoms of each element a molecule containsEx: H2O contains 3 atoms (2 atoms of H, 1 atom of O)

C2H6 contains 8 atoms (2 atoms of C, 6 atoms of H)

Ionic vs. Covalent

IONIC COVALENT

Bonded Name Salt Molecule

Bonding Type Transfer e- Share e-

Types of Elements Metal & Nonmetal Nonmetals

Physical State Solid Solid, Liquid, or Gas

Melting Point High (above 300ºC) Low (below 300 ºC)

Solubility Dissolves in Water Varies

Conductivity Good Poor

Practice

How many atoms total and of each do the following molecular compounds contain?

1. H2

2. CO

3. CO2

4. NH3

5. C2H6O

Practice: True or False

1. All molecular compounds are composed of atoms of two or more elements.

2. All compounds are molecules.

3. Molecular compounds are composed of two or more nonmetals.

4. Atoms in molecular compounds exchange electrons.

5. Molecular compounds have higher melting and boiling points than ionic compounds.