Molecular compounds are formed when two or more different non-metal atoms combine via covalent bonds, sharing electron pairs. Examples include water, which is made of two hydrogen atoms bonded to one oxygen atom. Molecular compounds have properties like being soft and having low melting points. They are named systematically with the first element, the second as an "-ide", and prefixes to indicate atom amounts, like dinitrogen monoxide for N2O.

1. Compounds
Part two: Molecular compounds

2. Molecular Compounds
• A molecule is a combination of
two or more atoms held
together by covalent bonds
• A covalent bond occurs
between the atoms of non-
metals in which the two atoms
share a pair of electrons

3. Molecular Elements
• A molecular element is when
two or more atoms of the same
element are joined by covalent
bonds
• A diatomic molecule is a
molecule that is made from two
atoms e.g.) the element chlorine
is a diatomic molecule (Cl2)

4. Molecular Compounds
• When atoms of two or more
different non-metals combine,
a pure substance known as a
molecular compound is
formed

5. Molecular Compounds
• As with molecular elements,
the atoms in molecular
compounds are joined
together by covalent bonds
• In each bond, the atoms share
a single pair of electrons.

6. Molecular Compounds
• For example, water is a
molecular compound with two
covalent bonds
• Each hydrogen atom shares
one pair of electrons with an
oxygen atom

7. Properties of Molecular
Compounds
• soft
• low melting point
• solutions do not conduct
electricity

8. Naming Molecular
Compounds
For compounds that do not
contain hydrogen:
1. Name the first element
2. Name the second element and
change the ending to “-ide”
3. add prefixes to indicate the
number of each atom

9. Naming Molecular
Compounds
• The prefix “mono” is not used
when there is only one atom
of the first element
• When “mono” is being added
to oxygen, the last “o” is
dropped (e.g. “monoxide” not
“monooxide”)

10. Naming Molecular
Compounds
Example 1: N2O
• Name the first element:
nitrogen
• Name the second element
using “-ide”: oxide
• Add prefixes:
dinitrogen monixide

11. Naming Molecular
Compounds
Example 2: PBr3
• Name the first element:
phosphorous
• Name the second element
using “-ide”: bromide
• Add prefixes:
phosphorous tribromide

12. Naming Molecular
Compounds
• Hydrogen is unique in many
ways, and this is reflected in the
naming systems
• Many compounds containing
hydrogen have been given
simpler names
• For example, dihydrogen
monoxide (H2O) is simply
called “water”

13. Naming Molecular
Compounds