TEKS 7.7 B and C

Let’s get physical with science!

TAKS Objective 3 – The student will demonstrate an understanding of the structures and properties of matter.

Learned Science Concepts:

Matter is composed of atoms.

Substances have chemical and physical properties.

Complex interactions occur between matter and energy.

TEKS Science Concepts 7.7

The student knows that substances have chemical and physical properties. The student is expected to:

(B)describe physical properties of elements and identify how they are used to position an element on the periodic table; and

(C)recognize that compounds are composed of elements.

Science Concept 7.7 B

Overview

The students will first define property and learn to identify physical properties of given objects. The characteristic physical property of density will be explored. They will then group given items based on similar physical properties. They will use their knowledge of properties and organizing objects according to their properties, to examine the arrangement of the periodic table. Substances on the periodic table will be identified as pure elements that may be combined to form compounds, the form in which most substances exist.

Instructional Strategies

Students will identify physical properties by constructing ornaments and identifying their physical properties. The ornaments constructed will then be organized into categories according to their physical characteristics. Hands-on activities such as cutting and pasting, coloring, and making models will also be implemented to teach the arrangement of the periodic table and the composition of a compound.

Objectives

  1. The student will describe the physical properties of an element.
  2. The student will demonstrate knowledge of physical properties by making an ornament and listing five physical properties of that ornament.
  1. The student will organize ornaments by similar physical properties.
  1. The student will label the periodic table according to groups that contain similar properties.
  1. The student will demonstrate that density is a characteristic property.
  2. The student will explain how properties are used to place elements on the periodic table.
  3. The student will label the periodic table according to groups that contain similar properties.
  4. The student will demonstrate how compounds are composed of elements.

Physical Properties For Teacher’s Eyes Only

If we are to examine and explore matter, we must have a way to describe our observations about matter. We call these observations, “properties”. Properties are divided into two major groups: chemical and physical.

Physical properties are those that describe what the matter is like (what does it look like, feel like, taste like, etc.). They are those properties that can be observed with our senses. Examples of physical properties are: color, size, shape, density, melting point, boiling point, freezing point, odor, and texture.

Chemical properties describe how matter behaves (what does it do when one type of matter encounters or reacts with another. They refer to the matter’s ability to change into another type of matter with different properties. Those properties can only be observed when matter reacts or doesn’t react. Examples of chemical properties are: metal’s ability to rust (chemical reactivity), flammability, and combustibility,

A major test of whether or not a property is physical or chemical is whether or not the property may be observed without changing the identity of the substance. Physical properties do not change the identity. For example, is you wad up a piece of paper, it has a different shape, but it is still paper. A chemical property will change the identity of the matter. A chemical property of paper is that it will burn (flammability is the property) so when you burn a piece of paper, it is not longer paper. Gases have been released and ash remains, different substances than the paper.

Student Misconceptions

 Misconception

The characteristic properties of a substance change with the size or amount of the substance.

 Science Concept

Characteristic properties of a substance are the same regardless of sample size.

Rebuild Concept

Allow students to calculate the density of a substance such as clay. Divide the clay in half, then allow them to predict whether or not the density of the clay has changed. Allow them to calculate the new density.

 Misconception

Real chemicals are found in the chemistry laboratory and not around the house.

 Science Concept

Chemicals that are found around the house are usually more concentrated than teachers use with the students in lab due to safety issues at school.

Rebuild Concept

Have students look at various cleaners etc. around their house and record the ingredients in each. Discuss the chemical composition and danger warnings of those chemicals.

Student Prior Knowledge

Physical Properties5 E’s

Engage

Engage 1

Demonstration: Choose several objects. Keep them hidden out of view of the students. Describe each one using its physical properties as you observe the object inside a paper bag. Allow students to guess what each object is as you describe it.

Explore

Exploration

Activity: Ornamental Properties

Class Time: 20 minutes

Objective: The student will demonstrate knowledge of physical properties by making an ornament and listing five physical properties of that ornament.

.

Materials

The student may bring their own materials or use materials provided in class such as:

Construction paper

Clay

Scissors

Glue

Craft sticks

Balloons

Colored tissue

Procedure: The students will make ornaments to hang from the ceiling that represent whatever holiday happens to be close at hand. For example, near Halloween, they would do “pumpkin properties”. They would make pumpkin ornaments out of any desired material (weight and size should be limited), then name five physical properties of their pumpkin. The ornament must be able to be hung from the ceiling and the list of properties should be written on the back or attached in some way.

Explain

Physical properties are things that can be described about an object or material by observing it using the five senses. There are characteristic physical properties, such as density and state of matter,that do not change regardless of how much of the material is present.

Elaborate

Elaboration 1

Activity: The students will choose 10 of the ornaments that have been made and place them into categories based on their physical properties.

Class Time: 15 minutes

Objective: The student will organize ornaments by similar physical properties.

Elaboration 2

Activity: Density, a Physical Property

Class Time: 15 minutes

Objective: The student will demonstrate that density is a characteristic property.

Materials:

Student Worksheet – Density, a Physical Property

Water

50 ml graduated cylinder

100 ml graduated cylinder

Balance scale

Procedure: Students will measure out 50 ml of water then find the mass of 50 ml of water. They will then calculate the density of the water. Then they will do the same with 100 ml of water. They will then compare the density of different quantities of water to show that, at the same temperature, no matter how much water you have, the density is the same. It is a characteristic property of water.

Evaluate

Present students with three items. You may place them on a table or in a sack to be given to each student. The student must list five physical properties of each item.

Give each student a density chart and an unknown element. Allow them to identify the element based on its density.

Periodic Table For Teacher’s Eyes Only

The periodic table with which we are familiar was first organized in the 1860’s by a Russian chemist named Dmitri Mendeleev (Men-da-‘le-off). He took pieces of paper and wrote the name of each element and information about each element discovered at that time on separate pieces of paper. He included properties such as density, appearance, atomic mass, melting point, and compounds formed from the element. Then he arranged the papers in different ways hoping to see a pattern. When the elements were arranged in order of increasing atomic mass, he could see a pattern. Every eighth element had similar chemical and physical properties.

Mendeleev also predicted elements that had not yet been discovered at that time. Later gallium was discovered and matched his predictions very well. All of the missing elements on his table have now been discovered. A few of those elements however, were not in the correct place according to their properties.

A man named Henry Moseley suggested that arranging the elements in order of increasing atomic number instead of increasing atomic mass might solve the problem. He was right. Every element fell into its proper place. In 1914, the periodic chart was thus revised to list the elements according to his proposal and we still have that arrangement today.

There are two main groups on the periodic table: metals and nonmetals. The left side of the table contains elements with the greatest metallic properties. As you move from the left to the right, the elements become less metallic with the far right side of the table consisting of nonmetals. The elements in the middle of the table are called “transition” elements. A small group whose members touch the zigzag line are called metalloids because they have both metallic and nonmetallic properties.

The table is also arranged in vertical columns called “groups” or “families” and horizontal rows called “periods.” Each arrangement is significant. The elements in each vertical column or group have similar properties. Group 1 elements all have one electron in their outer shells. This gives them similar properties. Group 2 elements all have 2 electrons in their outer shells. This also gives them similar properties. Not all of the groups, however, hold true for this pattern. The elements in the first period or row all have one shell. The elements in period 2 all have 2 shells. The elements in period 3 have 3 shells and so on.

There are a number of major groups with similar properties. They are as follows:

Hydrogen: This element does not match the properties of any other group so it stands alone. It is placed above group 1 but it is not part of that group. It is a very reactive, colorless, odorless gas at room temperature. (1 outer level electron)

Group 1: Alkali Metals – These metals are extremely reactive and are never found in nature in their pure form. They are silver colored and shiny. Their density is extremely low so that they are soft enough to be cut with a knife. (1 outer level electron)

Group 2: Alkaline-earth Metals – Slightly less reactive than alkali metals. They are silver colored and more dense than alkali metals. (2 outer level electrons)

Groups 3 – 12: Transition Metals – These metals have a moderate range of reactivity and a wide range of properties. In general, they are shiny and good conductors of heat and electricity. They also have higher densities and melting points than groups 1 & 2. (1 or 2 outer level electrons)

Lanthanides and Actinides: These are also transition metals that were taken out and placed at the bottom of the table so the table wouldn’t be so wide. The elements in each of these two periods share many properties. The lanthanides are shiny and reactive. The actinides are all radioactive and are therefore unstable. Elements 95 through 103 do not exist in nature but have been manufactured in the lab.

Group 13: Boron Group – Contains one metalloid and 4 metals. Reactive. Aluminum is in this group. It is also the most abundant metal in the earth’s crust.(3 outer level electrons)

Group 14: Carbon Group – Contains one nonmetal, two metalloids, and two metals. Varied reactivity. (4 outer level electrons)

Group 15: Nitrogen Group – Contains two nonmetals, two metalloids, and one metal. Varied reactivity. (5 outer level electrons)

Group 16: Oxygen Group – Contains three nonmetals, one metalloid, and one metal. Reactive group. (6 outer level electrons)

Groups 17: Halogens – All nonmetals. Very reactive. Poor conductors of heat and electricity. Tend to form salts with metals. (7 outer level electrons)

Groups 18: Noble Gases – Unreactive nonmetals. All are colorless, odorless gases at room temperature. All found in earth’s atmosphere in small amounts. (8 outer level electrons)

MISCONCEPTIONS

 Misconception

Groupings are clear cut.

 Science Concept

Although clear patterns are shown within each group, there is no distinct division that places an element clearly in a specific group. Each group must be looked at as a whole.

Rebuild Concept

Ask students to research elements in two different groups with very similar qualities. Discuss how the table is arranged and how the elements are chosen to be in each group.

 Misconception

All the elements in one group have the same properties.

 Science Concept

Even though each group has similar properties, not every member of the group has the same properties. There is a lot of variation.

Rebuild Concept

Research and compare elements found in a single group. Discuss how the elements are different and how the arrangement of the table put them in that group.

Student Prior Knowledge

Periodic Table5 E’s

Engage

Engage (Blackline Master)

Cut apart the cells of the following table. Mix them up and place them in an envelope. Allow the students to work in small groups to place the cells in order so that they show a relationship both vertically and horizontally.

Materials:

Envelopes with pieces of paper that contain names of things that can be grouped in different ways such as modes of transportation (group by passenger capacity and medium of transport ei. water, land, air), students in the room (group by gender, race, hair color, height, etc.). The following list is a suggestion or you may allow the students to make up a list given a topic.

Motorcycle / Fishing boat
Helicopter / Train
Submarine / Hang Glider
Large Airplane / Bicycle
Scooter / Cruise ship
Truck / Car
Skateboard / Paddle boat
Skis / Bus

Procedure:

Students will arrange the words by two groupings: capacity and medium. (You may allow them to decide the two ways to group them or just tell them two ways.) They will make a table as follows:

KEY:

Individual / Small Group / Large Group
Water / Paddle boat / Fishing boat / Cruise ship Submarine
Air / Hang Glider / Helicopter / Large Airplane
Land / Bicycle Scooter Skis
Motorcycle / Car Truck / Train
Bus

GROUP IT! (Blackline Master)

Student Worksheet

Purpose: To demonstrate that things can be classified both vertically and horizontally to show their properties.

Materials:

Envelope with names of different types of transportation.

Student Worksheet

You have been given an envelope with names of different kinds of transportation. Arrange each word on the table to reflect two classifications: the medium that type of transportation uses and its capacity.


Individual / Small Group / Large Group
Water
Air
Land

Explore

Exploration

Activity: Periodic Parallels (Blackline Master)

Class Time: 30 minutes

Objective: The student will label the periodic table according to groups that contain similar properties.

Materials: A copy of the Student Information Sheet and the Student Worksheet “Periodic Parallels”. (See Blackline Masters: Explore – Periodic Parallels)

Procedure: The students will cut and paste labels on a copy of the periodic table according to groups with similar properties.

Explain

The periodic table is organized to show relationships vertically and horizontally. The elements in a vertical column (called group or family) have the same number of electrons in their outer energy levels. Each element in a particular horizontal row (called a period) has the same number of energy levels as every other element in that particular row. Because elements have the same number of outer level electrons, they exhibit similar properties. Some groups are named because of the properties that they share. For example, the word “halogen” means “salt-former”. The elements in group 17 tend to form salts when combined with other non-metals or metals. They are also poor conductors of electric current, react violently with alkali metals to form salts, and are never found uncombined with other elements in nature.

Elaborate 1

Student will play the Jeopardy Periodic Table Game. The teacher will use the Jeopardy Periodic Table PowerPoint on the Xtreem Science Website.

Elaborate 2

Students will do research to find examples of properties shared by each specific group on the periodic table. For example, alkali metals react violently with water and are soft, silvery, and shiny. Elements in the actinide period are all radioactive.

Evaluate

Students will be given a blank copy of the periodic table to fill in with the correct names of the specific groups. (See Blackline Masters – Evaluate – Periodic Parallels)

TAKS Objective 3page 1

TAKS Objective 3page 1

Density, a physical property

Elaboration 2

In this activity, you will find the density of different amount of water to find out whether or not density is a characteristic property of water.

Problem: Does density change when the amount of water changes?