Ionic compounds• When an atom gains or loses electrons,

the atom is no longer neutral. It has become an ion.

• An ion has either a positive or a negative charge.

• Ions do not have an equal number of protons and electrons like atoms do.

Sodium atoms can become ions• When a sodium atom (a metal) loses

an electron, it becomes a sodium ion. It has an overall positive charge and it no longer has its original properties.

Chlorine atoms can become ions• When a chlorine atom (a non-metal) gains an electron, it becomes a

chlorine ion. It has an overall negative charge and no longer has its original properties.

Na+ and Cl- attract each other

• Because Na+ and Cl- are oppositely charged, they will attract each other and form an ionic compound.

• NaCl has very different properties than either sodium or chlorine as neutral atoms.

Ionic compounds conduct electricity

Naming molecular compounds

Naming molecular compounds

• Chemistry is done all over the world• To avoid confusion, scientists have

come up with a universal way to name chemical compounds

• The group that is in charge of setting standards for naming chemical compounds is called the International Union of Pure and Applied Chemistry (IUPAC)

IUPAC naming rules for molecular compounds1. Write the entire name of the first element2. Change the ending on the name of the second element to “–ide”3. Use a prefix to indicate the number of each type of atom in the

formula: • 1 = mono*• 2 = di• 3 = tri• 4 = tetra• 5 = penta• 6 = hexa

* Mono is only used for the second element in the compound

Examples

1. Write the entire name of the first element

2. Change the ending on the name of the second element to “–ide”

3. Use a prefix to indicate the number of each type of atom in the formula: • 1 = mono*• 2 = di• 3 = tri• 4 = tetra• 5 = penta• 6 = hexa

* Mono is only used for the second element in the compound

1. H₂O is named dinitrogen monoxide

2. NO is named nitrogen monoxide

3. NH3 is named nitrogen trihydride

CCl₄

Carbon tetrachloride

N2O₄

Dinitrogen tetraoxide

Apollo-Soyuz Test Project 1975

https://en.wikipedia.org/wiki/Apollo%E2%80%93Soyuz_Test_Project

H2S “sour gas”

Working on the side of a volcano

Writing the chemical formula from the name

If you are changing from the written name of the compound to the formula:

1. Write the symbols for the elements in the same order as they appear in the name

2. Use subscripts to indicate the numbers of each type of atom

Examples:1. What is the chemical formula

for dinitrogen monoxide?N2O

2. What is the chemical formula for silicon dioxide?

SiO23. What is the chemical name

for phosphorus trichloride?PCl3

Naming binary ionic compounds

Naming binary ionic compounds

Two rules for naming binary ionic compounds:1. The first element in the name and formula is the metal2. The second element, the non-metal, is named as an ion.

In other words, the suffix “-ide” is attached to the name.

Example: the compound formed from lithium and fluorine is named lithium fluoride

Examples

The compound formed from sodium and chlorine is named sodium chloride

The compound formed from magnesium and nitrogen is named magnesium nitride

You try…The compound formed from magnesium and oxygen is named…?

magnesium oxide

The compound formed from lithium and bromine is named…?lithium bromide

The compound formed from beryllium and phosphorus is named…?

beryllium phosphide

Review: formulas for binary ionic compounds

The chemical formula shows the simplest whole number ratio of each type of ion in the compound.

Example: the formula CaF₂ indicates that any crystal of calcium fluoride contains two fluoride ions for every one calcium ion (2:1 ratio of fluorine to calcium)

Review: formulas for binary ionic compounds

To determine the formula for any binary ionic compounds, use the periodic table to determine the number of transferred electrons between the two elements.

For groups 1, 2, and 13-18 you can use the group number to determine the common charge

Create a Venn diagram for naming molecular and ionic compounds