chapter 12 elements and their properties. objectives 12.1 describe the properties of a typical metal...

Chapter 12 Elements and Their Properties

Objectives

• 12.1 Describe the properties of a typical metal • 12.1 Identify the alkali and alkaline earth

metals • 12.1 Differentiate between three groups of

transition elements

Minor Objectives

• 12.2 Distinguish among elements classified as lanthanides, actinides, and transuranium elements

• 12.2 Determine the uses of transuranium elements

• 12.2 Compare the pros and cons of making new elements

Objectives

• 12.3 Recognize hydrogen as a nonmetal • 12.3 Compare and contrast properties of

halogens • 12.3 Describe properties and uses of noble

gases

Objectives

• 12.4 Distinguish among metals, nonmetals, and metalloids

• 12.4 Describe the nature of allotropes• 12.4 Recognize the significance of differences

in crystal structure in carbon

Metallic BondingWhat is a Metallic Bond?

- A metallic bond occurs in metals. A metal consists of positive ions surrounded by a “sea” of mobile electrons.

Name 4 Characteristics of a Metallic Bond.

1. Good conductors of heat and electricity

2. Great strength

3. Malleable and Ductile

4. Luster

This shows what a metallic bond might look like.

Definition of Words

• Malleable: Bendable, can be hammered to be thinner or rolled up in sheets

• Ductile: Stretchable, can be pulled apart like laffy taffy

• Luster: Reflects light, looks shiny

Alkali Metals

– First column (one word)• Highly Reactive, not found in nature by

themselves• React with Water• Lose 1 Electron

Alkaline Earth Metals

– Second Column (Two words)• Some are found in nature by themselves (Top

of column) such as Magnesium– Not as reactive as the Alkali Metals

• Lose Two electrons• Calcium: Bones• Magnesium: Muscles (as well as bones)

Transition Metals

– Less reactive than other metals to left. • General Rule for metals is closer to bottom

left, more reactive• Important sections include Iron Triad, Coinage

Metals

Iron Triad

• Iron, Cobalt, Nickel• Only common metals known to create a

magnetic field• Iron second most abundant element among

metals in crust– Aluminum is first

Coinage Metals

• Copper, Silver, Gold• Very unreactive, which leads to be being able

to be used as money• These also are the best conductors out of all

the metals – Silver > Copper > Gold

• Silver plays role also in photography

Other notables

• Zinc and Cadmium: Used to coat other metals for protection from rust (They do rust, but maintain good strength)

• Mercury: Liquid metal at room temperature, poisonous

Metals in the Crust

• Oxygen 47%• Silicon 28%• Aluminum 8%• Iron 5%• Calcium 3.6%• Sodium 2.8%• Potassium 2.6%• Magnesium 2.1%

12 -2 Transuranium Elements

• Uranium is largest atom that exists naturally (92 Protons)

• Elements beyond Uranium are synthetic (made in laboratory)– Smash elements together at super speeds to

collide and hopefully fuse• Is it worth it? They hope so, you may

disagree.

12-3 Non-Metals

• Properties of Non-Metals• Dull, Brittle, Powdery• Non-Metals alone tend to be gases at room

temperature• Tightly Held Electrons• Can form ionic or covalent bonds

Hydrogen

• Most abundant element in universe (75 – 90%) depending on what you read– Number continues to drop… via fusion

• A non-metal which tends to be fairly reactive (flammable, central to the role of acid/base)

• Diatomic– Di means 2 atoms. Hydrogen Gas means 2

Hydrogens bound• Dr. HOFBrINCl (all of the diatomic)

Halogens

• “Salt Makers”• Have 7 valence electrons, exist

diatomically• Very reactive (Flourine most)• Uses include: Etching glass,

cleaning pools, keeping water safe, dyes (including lipstick), and warfare

Noble Gases

• Name comes from nobles not hanging out with the common folk.

• Full outer shell. Inert (Unreactive)

• Used in locations of high heat, light bulbs, blimps, storage of reactive elements

Boron’s Column

• Many are semiconductors (used by computers)

• Aluminum is used all over the place (most abundant metal in crust)

• Boron used in eyewash (boric acid) and water softeners

Carbon Group

• Carbon: Basis of organic life (the definition of organic – does it have carbon?)

• Allotropes – Same element, different molecular structures– Carbon has many – graphite, diamond, fullerenes,

coal• Silicon – Sand component• Lead – poisonous, used in ancient rome/paints

Nitrogen’s Group

• Nitrogen makes up 80% of atmosphere• Nitrogen – needed by plants (not in gas form,

nitrates) as fertilizer• Phosphorus – Matches (as well as fertilizer)– Allotropes – Red and White matches

Oxygen’s Group

• Similar properties to halogens• Oxygen 20% of atmosphere– Allotropes – oxygen and ozone

• Sulfur – Used in paints (pigments) and battery acid (Sulfuric acid)