» Please take out your periodic table.

Ionic Compounds

Before we begin… What are ions? How are they made?

(Hint: Remember what happens to VALENCE electrons.)

(Put a line down the middle of the white board.) On one half draw a Bohr diagram for sodium. Make it stable (that is, make it into an ION.) What charge does it have?

On the other half, draw a Bohr diagram for chloride. Make it stable (that is, make it into an ION.) What charge does it have?

Ionic Compounds• Ionic compounds form when metals (+) combine with

non-metals (-) to make a NEW ionic compound • eg., sodium + chlorine —> sodium chloride • All ionic compounds have similar physical

properties… What are they? • It’s up to you to find out!!!

• What are examples of physical properties?

Conductivity is a physical property. How do we test for conductivity?

Purpose - A. To test ionic compounds to find out the common properties

Part B: (You will be given two “Mystery Chemicals” to determine if they are ionic or not!)

• are all white crystals • are formed between metals and non-metals • conduct electricity • are malleable • dissolve in water • are all toxic • have high melting points • are fragile and can shatter • are all crystals

Ionic Compounds:

• . • are formed between metals and non-metals • conduct electricity • . • dissolve in water • . • have high melting points • are fragile and can shatter • are all crystals

Ionic Compounds:

• Examine the table below. Which compound is an example of an ionic compound? Explain how you know.

Description Melting Point Solubility Conductivity

A- white square crystals 186 oC Yes No

B- white powder

175 oC No No

C - yellow crystals

1176 oC Yes Yes

What are Ionic Compounds?

Remember…• Metals ions have a ( + ) charge = CATIONS

-2

• Non metals ions have a ( - ) charge = ANIONS

+2Mg

O

X

X

X X

XX

X

X

X

XX X

Mg

X

XX

XX

XX X

X

X

+2 -2

Ionic Compounds

- are made by the combination of a metal (positive ion) and

a non- metal (negative ion).

eg., sodium + chlorine —> sodium chloride

magnesium + oxygen —-> magnesium oxide

General properties of Ionic Compounds

• are usually solids and form crystals.

• known as salts

• have High melting point

• are brittle and shatter under pressure

• When dissolved in water they conduct electricity

How do ionic compounds conduct electricity?

• Salt crystal has even patterns of the metal and non-metal in a crystal

• When dissolved, the ions separate in water

Let’s Make Ionic Compounds!

Metal Non-Metal Formula Name

magnesium oxygen MgO magnesium oxide

calcium chlorine CaCl2 calcium chloride

Lithium sulfur Li2S lithium sulfide

Lithium nitrogen Li3N lithium nitride

Metal Non-Metal Formula Name

calcium oxygen

Lithium sulfur

calcium nitrogen

magnesium oxygen

Magnesium nitrogen

CaO

Li2S

Ca3N2

MgO

Mg3N2

calcium oxide

lithium sulfide

calcium nitride

magnesium oxide

magnesium nitride

Forming Ionic Compounds• (Using pencil & paper and getting the same answer!)

To make the formula follow three easy steps 1. Write the symbols for each element with the metal first. 2. Write the ionic charge above each symbol 3. Crisscross the numbers, drop the (+,-) signs and write the

them as subscript

Lithium + Oxygen

Li O2-1+

Li O2 1Li2O

2

3-

Magnesium and Nitrogen

3

2+

1. Write the symbols for each element with the metal first. 2. Write the ionic charge above each symbol 3. Crisscross the numbers, drop the (+,-) signs and write the

them as subscript

Naming Ionic Compounds

1. Name the metal first 2. Name the non metal second. Change

the ending of its name to ‘ide’.

Mg3N2 Li2O Al Cl3Magnesium Nitride Lithium Oxide Aluminum Chloride

3

3+

1. Write the symbols for each element with the metal first.2. Write the ionic charge above each symbol 3. Crisscross the numbers, drop the (+,-) signs and write the

them as subscript

Chlorine and Aluminum

1

1-Al Cl

Al Cl AlCl3

2

2+

1. Write the symbols for each element with the metal first.2. Write the ionic charge above each symbol 3. Crisscross the numbers, drop the (+,-) signs and write the

them as subscript

Calcium and Oxygen

2

2-Ca O

Ca O CaO

The formula reduces to lowest terms whenever possible since the subscripts have a common factor

potassium & sulfer potassium sulfide K2S

magnesium & oxygen magnesium oxide MgO

calcium & nitrogen calcium nitride Ca3N2

Classwork

» Complete page 1 of the handout & keep in your notebook.

1. magnesium & oxygen 2. Lithium & sulfur 3. calcium & nitrogen