Molecular CompoundsMr. MacMillan

Naming Binary Ionic Compounds

There are two ways to identify a compound: Chemical Name Chemical Formula

IUPAC International Union of Pure and Applied

Chemistry Binary Ionic Compounds

Compound composed of a metal cation and a non-metal anion

Rules for Naming1. The first part of the name always

identifies the positive ion, which is the metal cation. Thus, this part of the name is the name of the metal.

2. The second part of the name always identifies the negative ion, which is the non-metal anion. The name of the non-metal ion always ends with the suffix ide.

Blue – Metals Teal – Non-metals Light Purple - Metalloids

Examples Magnesium and Phosphorus

Magnesium phosphide Sodium and chlorine

Sodium chloride

Determining the Chemical Formula

Cross-over methodIdentify the metal and non-metal1. Write the symbols2. Write the charges3. Cross over the charges from top to

bottom4. Remove the charge5. Simplify the numbers and remove the

1’s

Electron Dot Diagram and Bohr-Rutherford

Bohr-Rutherford

Electron Dot (Only showing valence electrons)

Multivalent Metals Metals that have more than one ion

charge listed in the periodic table. They can form different Ions depending on

the chemical reaction

Examples: Copper, Lead, Tin, Iron

Ionic Compounds with Polyatomic Ions

Polyatomic Ion An ion that is composed of more than one

atom. Ternary compound

A compound composed of three different elements

Most end in ite or ate

Molecular Compounds Also known as covalent compounds, are

usually composed of two or more different non-metals

Atoms share a pair of electrons to form a covalent bond

The stability is associated with a full outer energy level of electrons

Molecules A neutral particle composed of two or

more atoms joined together by covalent bonds

The term molecule is also used to describe two or more atoms of the same element.

H2 O2

Naming Binary Molecular Compounds A compound composed of two non-

metals joined by one or more covalent bonds.Prefix Number

Mono 1

Di 2

Tri 3

Tetra 4

Penta 5

Hexa 6

Hepta 7

Octa 8

How to Name Binary Compounds1. Count the number of atoms of the first element

in the chemical formula2. Write the appropriate prefix followed by the

name of the element (mono is never used for first element)

3. Count the number of atoms of the second element in the chemical formula

4. Write the appropriate prefix followed by the name of the element using the suffix ide. If the prefix ends with a or o, this letter is dropped before oxide

Your Turn

1. CS2

2. CCl43. Si2 Br6

Answers

4. Carbon disulfide5. Carbon tetrachloride6. Disilicon hexabromide

Writing Chemical Formulas1. Write the chemical symbol of the 1st element2. Determine the number of atoms of the 1st

element based on the prefix.3. Write the chemical symbol of the second

element.4. Determine the number of atoms of the 2nd

element based on the prefix.5. Write the chemical formula for the compound,

using the appropriate subscripts.

Your Turn1. Write the chemical formula for each binary

molecular compound.a) Nitrogen trifluorideb) Sulfur difluoridec) Diphosphorous hexoxide

Answersa) NF3

b) SF2

c) P2 O6