ION QUIZ

Today you will need your periodic table/ion sheet and your packet

Warmup (3 minutes)

1. What is a valence electron?2. Draw the Lewis dot structures of

magnesium and fluorine.3. What does the term “neutral” mean

(in terms of math and science)?

Is the red guy a cation or an anion?

Is the red guy a metal or a nonmetal?

Chemistry puts the "cation" in education. What's a cation afraid of?

A dogion!

Metal atoms lose e- to form positive ions called cations:

K+

Ca 2+

NH4+

Nonmetal atoms gain e- to form negative ions called anions:

Cl-

S2-

CO32-

Mg2+

Superscript written to the upper right shows the charge

F-

If the charge is +1 or -1, you don’t have to include the “1”

Called an “oxidation number”

Ion: An atom (or group of atoms) that has lost or gained e- to follow the Octet Rule and is now electrically charged

IonizationF + e- F-

Neutral but unstable fluorine atom, F

Write the (oxidation) equation showing how magnesium becomes an ion

Same # electrons as neon, but NOT an atom of neon!

Mg Mg2+ + 2e-

Same # e- as…which element?

Write the (reduction) equation showing how flourine becomes an ion

1A metals: +1 ions 2A metals: +2 ions

7A nonmetals: -1 ions 6A nonmetals: -2 ions

What patterns do you see? Are there any exceptions to

these patterns?

Special ions(refer to handout)

Some transition metals lose different numbers of electrons when they become ions

They can have different charges as a cation, and must be written with roman numerals representing their charge (exception: Al3+)

Examples?

Polyatomic ions: group of more than one atoms with a charge (+ or -)

Example: Why do chemists like nitrates so much?

They're cheaper than day rates.

Nonmetal atoms remove e- from metal atoms.

Ionic Bonds

The two atoms become oppositely charged ions that attract each other, resulting in an ionic bond. An ionic compound forms.

Na+

Cl-

Read through EX 1 on “Writing and Naming Ionic Compounds” Handout that shows the crisscross method.

EX 2: Write the formula for the ionic compound calcium oxideStep 1: Write each ion with the correct charge. Look at periodic table group or cheat sheet for help. Ca2+ O2-

Step 2: “Criss-cross” number associated with each charge (do not include the + or -) Ca2O2

Step 3: Remove any subscripts of 1. Eliminate both subscripts if they are the same. Write the formula.CaO

EX 3: Write the formula for the ionic compound aluminum carbonate

Al3+ CO32-

Al2CO33 ????

Al2(CO3)3

another example: iron(II)phosphateFe2+ PO4

3-

Fe2(PO4)3 NOOOOOOO!

Fe3(PO4)2

Fe 2+ PO43-

Fe 2+

Fe 2+

PO43-

Fe 2+

PO43-

Fe 2+

Fe 2+

PO43-

Fe 2+

PO43-

Fe 2+Fe 2+

PO43-

6+6-

Ionic compounds aren’t present as individual molecules, they exist as large crystals with many many of the same ions. The subscripts show the RATIOS of the two ions --- one formula unit of this compound has 3 iron(II)’s and 2 phosphates.

3:2 is simplified from 6:4

or 30,000:20,000

Name Formula

potassium nitride

copper (I) bromide

potassium phosphide

magnesium fluoride

K3N

CuBr

K3P

MgF2

Name these 2 compounds:CoSa.Figure out which ions

form the compound because the ion charge could be important.

Since S forms S2-, Co must be Co2+

b. Name the ions, cation first, then anion

c. Change ending to –ide if it’s a pure element.

cobalt (II)sulfide

d. Transition metals always get a roman numeral to indicate their charge!

Na2SO3

sodium sulfiteCommon mistakes:sodium(II)sulfitesodium(I)sulfitesodium sulfide/sulfate

Formula NameNa2O

CuS

LiBr

CuCl

Sodium Oxide

Copper (II) Sulfide

Lithium Bromide

Copper (I) Chloride

Name Formula

Ammonium Phosphate

Iron (II) Nitrate

Sodium Sulfate

Silver Acetate

(NH4)3PO4

Fe(NO3)2

Na2SO4

AgC2H3O2

Formula NameFe(OH)3

Mg(NO2)2

NiCO3

Cd(HCO3)2

Iron (III) Hydroxide

Magnesium Nitrite

Nickel (II) Carbonate

Cadmium (II) hydrogen carbonate

orCadmium (II) bicarbonate

Name FormulaSodium Dichromate

Tin (II) Chromate

Magnesium Permanganate

lead (IV) bisulfate

Na2Cr2O7

SnCrO4

Mg(MnO4)2

Pb(HSO4)4

Work on your packet!

Make sure you have the Precipitation Lab with you

next class!