Formation of Ions

• Atoms lose or gain electrons only from their outermost energy level (valence shell)

• The number of electrons lost or gained determines the “ion charge”. An ion is a “charged” atom (+) or (-).

• One electron lost leaves an atom with one extra proton which gives it a 1+ charge.

• One electron gained gives an atom a 1- charge

How Ions Form

• Atoms try to have the same number of outer electrons as the Noble Gas atom closest to it (which is usually 8 outer electrons).

• Nonmetals tend to gain 1, 2, or 3 electrons to have 8 outer electrons (form – charged ions).

• Metals tend to lose their 1, 2 or 3 outer electrons to go down to the next energy level with 8 outer electrons (form + charged ions).

Warm ups Atom Group Period Number of

outer electrons

Ion charge Lewis dot diagram

Cl

F

Ba

C

Ne

S

O

Remember in the Lewis Dot diagram, you only put the electrons in the outer most shell.

Warm ups Atom Group Period Number of

outer electrons

Ion charge Lewis dot diagram

Cl VII A 3 7 1-

F VII A 2 7 1-

Ba II A 6 2 2+

C IV A 2 4 4+ or 4-

Ne VIII A 2 8 none

S VI A 3 6 2-

O VI A 2 6 2-

Remember in the Lewis Dot diagram, you only put the electrons in the outer most shell.

• Reminders: • 1. In a neutral atom the number of protons

equals the number of electrons. • 2. An atom can NEVER gain or lose protons • 3. The number of protons equals the atomic

number

Write the ion for each of the following elements based on their locations on the

periodic table

1. Fluorine F-1

2. Magnesium 3. Aluminum4. Sodium5. Nitrogen 6. Hydrogen 7. Argon 8. Barium 9. Sulfur

Check with your seat mate when you are done.

Write the ion for each of the following elements based on their locations on the

periodic table

1. Fluorine F1-

2. Magnesium Mg2+

3. Aluminum Al3+

4. Sodium Na1+

5. Nitrogen N3-

6. Hydrogen H1+

7. Argon Ar (no charge)8. Barium Ba2+

9. Sulfur S2-

Check with your seat mate when you are done.

Write the ion for each of the following elements based on their locations on the

periodic table Answers:1. Fluorine F1-

2. Magnesium Mg2+

3. Aluminum Al3+

4. Sodium Na1+

5. Nitrogen N3-

6. Hydrogen H1+

7. Argon Ar (no charge)8. Barium Ba2+

9. Sulfur S2-

Check with your seat mate when you are done.

Now we are writing compounds

Hydrogen + Fluorine H+1 + F-1 HFHydrogen Fluoride

Magnesium + Sulfur Mg+2 + S-2 MgS+2 + -2 0 Magnesium sulfide

Aluminum + Nitrogen Al+3 + N-3 AlN+3 + -3 0 Aluminum Nitride

WHAT IF CHARGES DON’T EQUAL 0

• Hydrogen + Sulfur H+1 + S-2

No match

H S

What can we do

• GET ANOTHER HYDROGEN

H

H S

NOW HAVE 2 HYDROGEN &1 SULFUR

Writing and Naming

H2S1 don’t write the 1

Like in math – you don’t write 1x just x

So it is H2S

name is hydrogen sulfide

Use the matching kits

Where I had the arrows they have lines – every line needs a partner

Remember – drop final syllable of

second element then add ide

Predicting Ionic ChargesGroups 3 - 12:

Many transition elements have more than one possible oxidation state.Iron(II) = Fe2+ Iron(III) = Fe3+

Predicting Ionic ChargesGroups 3 - 12:

Many transition elements have more than one possible oxidation state.Copper (II) = Cu2+Copper(I) = Cu1+

Practice: Use your Periodic Table to write balanced chemical formulas for:

• Magnesim Bromide• Sodium sulfide• Copper (I) oxide• Potassium nitride• Zinc iodide• Aluminum oxide• Nickel (III) sulfide

Practice: Use your Periodic Table to write balanced chemical formulas for:

• Magnesium Bromide Mg2+ Br1- = MgBr2

• Sodium sulfide Na1+ S2- = Na2S

• Copper (I) oxide Cu1+ O2- = Cu2O

• Potassium nitride K1+ N3- = K3N

• Zinc iodide Zn2+ I1- = ZnI2

• Aluminum oxide Al3+ O2- = Al2O3

• Nickel (III) sulfide Ni3+ S2- = Ni2S3

Group Ions• “Group Ion” – an ion that is made of a group

of atoms and more than one element that acts like a single ion

• Group ions can NOT be found on the Periodic Table, but you will be given a list of them.

• Group ions each have their own name and charge.

• Most Group ions have a negative charge and contain the element oxygen

Examples of Group Ions

• Nitrate = NO31-

• Sulfate = SO42-

• Hydroxide = OH1-

• Phosphate = PO43-

• Carbonate = CO32-

Writing Formulas with Group Ions

• Treat the ENTIRE GROUP as having that charge• If more than one of Group Ion is needed then

put the group into parenthesis ( NO31-)

• Put the subscripts for more than one group below and to the right of the parenthesis (NO3

1-)2 • Example of a formula Calcium nitrate Ca2+

NO31- balanced is Ca(NO3)2

Practice – Write these formulas of compounds with Group Ions

• Aluminum hydroxide• Sodium phosphate• Iron (III) sulfate• Barium carbonate• Copper (II) nitrate

Answers

• Aluminum hydroxide Al3+ OH1- = Al(OH)3

• Sodium phosphate Na1+ PO43- = Na3PO4

• Iron (III) sulfate Fe3+ SO42- = Fe2(SO4)3

• Barium carbonate Ba2+ CO32- = BaCO3

• Copper (II) nitrate Cu2+ NO31- = Cu(NO3)2

Writing Names of Chemical Formulas

• The name of the positive metal ion never changes• If the metal ion has more than one possible

charge then use parenthesis ( ) and put the ion charge as a Roman numeral in the ( )

• If the nonmetal is a single element then change the ending to “ide” Example: chlorine becomes “chloride”, oxygen becomes “oxide”

• Group Ions have their own name like NO31- is

nitrate, SO42- is sulfate

Practice: Name these ionic formulas

• AlCl3

• CaS• Cu(OH)2

• Na3N

• MgSO4

• PbO2

• AgCO3

Practice: Name these ionic formulas

• AlCl3 Aluminum chloride• CaS Calcium sulfide• Cu(OH)2 Copper (II) hydroxide

• Na3N Sodium nitride

• MgSO4 Magnesium sulfate

• PbO2 Lead (IV) oxide

• AgCO3 Silver carbonate