ChemistryMatter and Change

Chapter 7

Ionic Compounds and Metals

Previous

Ca: 1s22s22p63s23p64s2

Ar: 1s22s22p63s23p6

Draw the valence shell diagrams.

Ca is what element?

Ar is what element?

Compare Ca to Ar:

Calcium Argon

Both have 3 full shells of electrons, 1s, 2s and 2p, 3s and 3p.Calcium has 2 more electrons in the 4s shell.

Previous

Ca: 1s22s22p63s23p64s2

Ar: 1s22s22p63s23p6

Cl: 1s22s22p63s23p5

What element is Cl? Draw its valence shell diagram.

Compare Cl to Ar:

Previous

Ca: 1s22s22p63s23p64s2

Ar: 1s22s22p63s23p6

Cl: 1s22s22p63s23p5

What will it take for calcium and chlorine to be like argon?

Why would calcium and chlorine want to be like argon?

Previous

K: 1s22s22p63s23p64s1

Ar: 1s22s22p63s23p6

Draw the valence shell diagrams.

What element is K?

Compare and contrast:

Why is argon stable?

How can K become “Noble Gas” like?

Previous

Ca: 1s22s22p63s23p64s2

Ga: 1s22s22p63s23p64s23d104p1

What element is Ga? Draw its valence shell diagram.

Compare and contrast:

Important

“Noble Gas Like” means to have a full octet of valence electrons in the s and p orbitals.

The atoms do not become Noble Gases.

Only the atomic number determines the name of the element. The only way to change to another element is nuclear decay, remember the proton and neutrons are in the nucleus not the electrons.

7.1 Ion Formation

How do so many compounds form from the relatively few elements know to exist?

Chemical Bond

A chemical bond is the force that holds two atoms together.

One way is an attraction between the electron (-) on one atom and the nucleus of another (+).

Another way is the attraction between ions.

Valence Electrons

Electrons in the s and p orbitals only

Gp 1 2 13 14 15 16 17 18

Cation

Positively charged atom

Lose 1 or more electrons

Groups 1, 2 and 13

Group 1

Li: 1s22s1 or [He] 2s1

The outermost shell has 1 electron.

Remove 1 electron and lithium is like the Noble Gas helium, called lithium cation

Li1+

Group 1

Na: 1s22s22p63s1 or [Ne]3s1

The outermost shell has 1 electron.

Remove 1 electron and sodium is like the Noble Gas neon, called sodium cation

Na1+

Group 1

K: 1s22s22p63s23p64s1 or [Ar]4s1

The outermost shell has 1 electron.

Remove 1 electron and potassium is like the Noble Gas argon, called potassium cation

K1+

Group 2

Be: 1s22s12 or [He] 2s2

The outermost shell has 2 electrons.

Remove 2 electrons and beryllium is like the Noble Gas helium

Be2+

Group 2

Mg: 1s22s22p63s2 or [Ne]3s2

The outermost shell has 2 electrons.

Remove 2 electrons and magnesium is like the Noble Gas neon

Mg2+

Group 2

Write the Noble Gas electron configuration for Ca

Write the ion symbol.

Noble Gas Electron Configuration

Ca: [Ar]4s2

Ion Symbol Ca2+

Group 3

B: 1s22s2sp1 or [He] 2s22p1

The outermost shell has 3 electrons.

Remove 3 electrons and boron is like the Noble Gas helium

B3+

Group 3

Write the Noble Gas electron configurations for:

Al

Ga

Write the ion symbols.

Cations

Does removal of an electron from a neutral atom require or release energy?

Sodium atom Sodium ion

Formation of a Cation

Notice Smaller CloudWhy?

NoticeRequiresEnergy

Notice“free” electron

Metals

• Group 1 and 2 most reactive

• Form cations easy

Transition Metals

Have full s2 orbitals

Lose these 2 electrons and maybe one electron in the d orbital

Sometimes it is difficult to predict how manyImportant to write cation symbol

Fe2+ and Fe3+

Anion

Negatively Charged Ion

Gain one or more electrons

Name is changed: __suffex becomes __ide

chlorine chloride

nitrogen nitride

Group 17

Flourine wants to be neon like.

Has 7 valence electrons and wants 8

Gains 1 electron and has a -1 charge

Flouride F-

Group 17

Chlorine wants to be argon like.

Has 7 valence electrons and wants 8

Gains 1 electron and has a -1 charge

Chloride Cl-

Group 17

Bromine wants to be krypton like.

Has 7 valence electrons and wants 8

Gains 1 electron and has a -1 charge

Bromide Br -

Group 16

Oxygen wants to be neon like

Has 6 valence electrons and wants 8

Gains 2 electron and has a -2 charge

Oxide O2-

Group 16

Sulfur wants to be argon like

Has 6 valence electrons and wants 8

Gains 2 electron and has a -2 charge

Sulfide S2-

Group 16

Write the Valance Electron Diagram for Selinium, Se

What noble gas does it want to be like?

How many electrons does it need?

Write the name and symbol for the anion.

Valence Electron diagram

Wants to be like Krypton, Kr

Needs 2 electrons

Ion Se2-

Group 15

Find the number of valence electrons.

What noble gas do these elements want to be like?

Draw the electron dot structure for each.

Name the anion and write its name.

Nitrogen, Phosphorus and Arsenic

Fluorine atom Fluoride (ion)

Formation of an AnionNotice“free’ electron

NoticeSmaller cloudNow Larger cloud

NoticeEnergy Released

Compare

How do the energy changes accompanying positive ion and negative ion formation compare?

Questions p. 209

1. Compare the stability of a lithium atom with that of its ion, Li+.

2. Describe two causes of the force of attraction in a chemical bond.

3. Why are all of the elements in group 18 unreactive, whereas those in group 17 are very reactive?

4. Summarize ionic bond formation by correctly paring these terms: cation, anion, electron gain, electron loss.

5. Write out the electron configuration for each atom. Then predict the change that must occur in each to achieve a noble-gas configuration.

a. nitrogen b. sulfur c. barium d. lithium

6. Draw models to represent the formation of the positive calcium ion and the negative bromide ion.

Fluorine

1. Write out electron configuration

2. Calculate number of valence electrons

3. What ion forms? (symbol)

4. What is the name of the ion?

Each Student

Write 5 element symbols on a piece of paper with atomic number 54 or lower.

Switch papersWrite electron configuration for each

elementDraw electron dot diagramDetermine what type of ion is most likely

formed

Exit Ticket

Determine the ions formed for

Strontium

Aluminum

Sulfur