Focus Question: What are some properties of

metals?

Elements and Atoms 4-2Mixtures and Solutions

Organizing the Elements

• How many different elements occur naturally on Earth?

• How many different kinds of atoms occur naturally on Earth? Why do you think so?

• How was Mendeleyev able to predict the existence of elements that had not yet been discovered?

• What is atomic number? How is it used to create a periodic table?

Periodic Table Review

• Open text books to pg 48, Periodic Table of the Elements

• Elements are in order by atomic number

• Elements in columns have similar chemical properties

• Color is used to show groups of elements that have properties in common.

• Find the largest group of elements. What are some familiar ones in that group?

Metals• All metals share several properties. • Have a shiny luster when a fresh surface is exposed.

• Can be bent, stretched, and hammered into different shapes with out breaking.

• Metals have two other properties that nonmetals don’t.• Let’s see if we can figure out what they are.

Materials Test

• Aluminum• Metal? Element?

• Copper• Metal? Element?

• Brass• Metal? Element?• Not an element. No brass atom. • Mixture of two metals, copper and zinc.• Mixtures of metals are called alloys.• Are copper and zinc elements?• What kind of atoms do you think are in the metal alloy brass?

More Materials• Stainless steel

• Metal? Element?• Steel is an alloy of iron and other elements.

• Element that make steel stainless is chromium.

• Chromium is an element.• Stainless steel alloy contains iron and chromium atoms.

• Plastic• Metal? Element?

• Wood• Metal? Element?

Electric Conductivity

• When I touch the two wires together, electricity flows in the circuit and the light glows.

• Materials that allow the flow of electric current are called electricity conductors. The wires are electricity conductors.

• Which materials will conduct electricity?

Heat Conductivity• Predict what will happen to the paper clips stuck to the strips when I put the bottoms of the material strips in hot water.

• Materials that allow heat to flow through them are heat conductors.

Record Results• Complete Part 1 of Properties of Materials worksheet.

• Which materials conducted heat and electricity?

• Complete Part 2 of worksheet.

Review Responses• Which materials conducted both heat and electricity?

• What is the same about those materials?

• Which metal conducted heat best and which one conducted heat worst?• What is your evidence?

• Check the elements you think are good conductors of heat and electricity and explain why.

Vocabulary• Metals - most of the 90 naturally occurring elements on Earth are this. Metals have common properties.

• Alloy - mixtures of two or more metals are called metal alloys

• Electricity conductors - all metals conduct electricity

• Heat conductors - all metals conduct heat

Content• What properties do all metals share?• Metals are elements that are shiny, are shapable, and can conduct heat and electricity.

• Are metals alloys? How can you tell?• Yes, they have the universal properties shared by metallic elements.

• Your questions?• Homework - Read Metals and answer questions; pages 52-58.

Metals Review Questions

• What is an alloy?• What properties do all metals have in common?

• Which of these metals are elements? Which are alloys?• Nickel, bronze, steel, cobalt, chromium, alnico, gold, zinc, tin, brass