Big Idea 8: Properties of Matter

Atomic theory, properties of matter, atoms, compounds,

mixtures, & solutions

Benchmark Number & Descriptor SC.8.P.8.5

Recognize that there are a finite number of elements and that their atoms combine in a multitude of ways to produce compounds that make up all of the living and nonliving things that we encounter.

SC.8.P.8.6Recognize that elements are grouped in the periodic table according to similarities of their properties.

SC.8.P.8.7Explore the scientific theory of atoms (also known as atomic theory) by recognizing that atoms are the smallest unit of an element and are composed of sub-atomic particles (electrons surrounding a nucleus containing protons and neutrons).

SC.8.P.8.8Identify basic examples of and compare and classify the properties of compounds, including acids, bases, and salts.

SC.8.P.8.9Distinguish among mixtures (including solutions) and pure substances.

SC.8.P.8.1

Explore the scientific theory of atoms (also known as atomic theory) by using models to explain the motion of particles in solids, liquids, and gases.

SC.8.P.8.2

Differentiate between weight and mass recognizing that weight is the amount of gravitational pull on an object and is distinct from, though proportional to, mass.

SC.8.P.8.3

Explore and describe the densities of various materials through measurement of their masses and volumes.

SC.8.P.8.4

Classify and compare substances on the basis of characteristic physical properties that can be demonstrated or measured; for example, density, thermal or electrical conductivity, solubility, magnetic properties, melting and boiling points, and know that these properties are independent of the amount of the sample.

MATTEREverything in the world is made up of matter.

Matter is defined as anything that takes up space and has mass.

Atoms are the building blocks of matter.

Matter can exist as solids, liquids, gases and plasma.

Matter has both physical and chemical properties.

SOLIDS, LIQUIDS and GASES

Characteristics:

• Definite shape

• Definite volume

• Atoms are packed tightly together with very little movement.

SOLIDS

Characteristics:

• Definite volume

• Indefinite shape

Liquids will take the shape of the container they are in.

• Atoms within a liquid are loosely packed together and have fluid movement within the container.

LIQUIDS

Characteristics:

• Indefinite shape

Gases will take the shape of the container they are placed into.

• Indefinite volume

Gases will spread out in order to fill their containers.

• Atoms within a gas are in constant free movement. They will spread out and fill the space they are contained in.

GAS

View this clip to see solids, liquids and gasses in action.

http://www.harcourtschool.com/activity/states_of_matter/

Take a Look…

Don’t Forget, PLASMA

Characteristics:

• Indefinite shape

• Indefinite volume

Particles can move past one another.

• Plasma consists of a sea of ions and electrons and is a very good conductor of electricity and is affected by magnetic fields.

• Plasmas are heated to over 100 million degrees.

Knowledge Check

1. Identify and describe the particle arrangement in the state of matter that has no definite shape but does have a definite volume?

2. How do the particles of a gas differ from a solid?

3. Which phase consists of electrically charged particles at very high temperatures?

Knowledge Check

1. Identify and describe the particle arrangement in the state of matter that has no definite shape, but does have a definite volume?

Liquid; particles have some movement within their containers.

2. How do the particles of a gas differ from a solid?

Gas particles have much more movement. Indefinite shape and volume

3. Which phase consists of electrically charged particles at very high temperatures?

Plasma

PHYSICAL vs. CHEMICAL PROPERTIES

What is the difference?

Physical Property

What it Means

Density The amount of matter in a given volume

Boiling Point The temperature at which a substance changes from a liquid to a gas

Melting Point/Freezing Point

The temperature at which a substance changes from a solid to a liquid (liquid to solid)

Solubility The ability to dissolve in another substance

A. Are observed with the senses and can be determined without destroying the object.

B. Does not depend on how much of the substance you have – if it is the same substance it should have the same properties.

PHYSICAL PROPERTIES

A. Indicates how a substance reacts with something else

B. The original substance is changed into something new.

CHEMICAL PROPERTIESChemical Property

What it Means

Flammability The ability to burn

Reactivity Ability to react with oxygen, acid, water, or other substances

Let’s Review…

Another Identification MethodDENSITY

Amount of mass per unit volume

Density = Mass / Volume

No matter how much of a sample you have of a specific substance, the same substances will have the same densities.

COMMON MATERIALS

Water ………………………1.00

Glass………………………2.60 Granite…………………2.650 Bone……………………….1.85 Human Body………………

0.995 Butter…………………….0.94

SulfuricAcid……1.840

Ice……………………0.91

Carbon………………2.60

Kerosene…………0.80

Chalk……………………2.36

Salt……………………2.20

Coal………………………1.50

Sand…………………2.80

Cork…………………0.25

Densit ies of Common Materials(computed in grams per cubic cent imeter)

Weight

• the force which a given mass feels due to the gravity at its place

• Weight is measured in units of Force like Newton (which is the SI unit of Force).

• The weight of an object will change due to its location (gravitational pull).

Mass

• the amount of matter present in an object

• Mass of an object is measured by balancing it equally with another known amount of mass.

• The mass of an object does not change due to its location.

WEIGHT vs. MASS

KNOWLEDGE CHECK

Distinguish from the list below which are physical and chemical changes.

1. Boiling point2. Flammability3. Reacts with acid4. Bitter taste5. Ice melting6. Iron rusting7. Solubility8. Milk sours9. Wood rots

KNOWLEDGE CHECK

Distinguish from the list below which are physical and chemical changes.

1. Boiling point - Physical2. Flammability - Chemical3. Reacts with acid - Chemical4. Bitter taste - Physical5. Ice melting - Physical6. Iron rusting - Chemical7. Solubility - Physical8. Milk sours - Chemical9. Wood rots - Chemical

What makes up matter?

ATOMIC THEORY

What’s an atom?

• Atoms are the building blocks for matter.

• They are so small that the naked eye cannot even see one.

• Atoms contain three particles.

Protons

Electrons

Neutrons

3 Little Particles…

460 BCE: Democritus

Stated the smallest piece matter can be broken into was an “atom.”

From the Greek word, atomos, which means “indivisible.”

1807 : John Dalton (British chemist)

1st modern scientist to discuss the atom.

Stated that an atom was similar to a billiard ball – round, indestructible, solid sphere

If we can’t see atoms, how do we know about them?

1898: Sir Joseph John Thompson (British physicist)

Stated that inside an atom was a mixture of protons and electrons mixed together

His idea is referred to as the “Plum Pudding Model.”

1911: Ernest Rutherford (British physicist)

Stated that atoms are mostly empty space

Discovered the positive charged nucleus of an atom

Suggested that electrons circle the nucleus

Conducted the gold foil experiment

If we can’t see atoms, how do we know about them?

1913: Niels Bohr (Danish physicist)

Stated that electrons did not just randomly circle the nucleus. Instead, the circled in orbits

Each orbit contained a certain number of electrons and were located a specific distances from the nucleus.

Current Atomic Model

Based upon Bohr’s model

Orbits of electrons are referred as the electron cloud.

If we can’t see atoms, how do we know about them?

KNOWLEDGE CHECK Match each scientist to their Atomic Theory Model

1. Democritus A. Proposed that electrons were located throughout an

atom like plums in plum pudding

2. John Dalton B. Atom model had electrons surrounding the nucleus at a

specific distance.

3. J.J. Thompson C. Stated atoms were the smallest piece of matter

4. Ernest Rutherford D. Electrons surround the nucleus in an electron cloud.

5. Niels Bohr E. Atoms of the same element are alike, and atoms of different elements are different.

6. Current Atomic Theory F. Electrons move around the nucleus in certain paths.

KNOWLEDGE CHECK Match each scientist to their Atomic Theory Model

1. Democritus - C A. Proposed that electrons were located

throughout an atom like plums in plum pudding

2. John Dalton - E B. Atom model had electrons surrounding the

nucleus at a specific distance.

3. JJ Thompson - A C. Stated atoms were the smallest piece of matter

4. Ernest Rutherford - B D. Electrons surround the nucleus in an electron cloud.

5. Niels Bohr - F E. Atoms of the same element are alike, and atoms of different elements are different.

6. Current Atomic Theory - D F. Electrons move around the nucleus in certain

paths.

Everything around you!

Put the atoms together and what do you get?

Combination of ATOMS

When atoms are combined together, they create elements.

All known elements are located on the periodic table.

Dmitri Mendeleev, a Russian chemist, was the original founder of the periodic table.

* Arranged elements in order of increasing mass

Henry Moseley, a British scientist, is know as the founder of the modern day periodic table.

* Arranged elements in order of increasing atomic number

MODERN PERIODIC TABLE

PERIODIC TABLE SET-UP

CO

LUM

NS

Also called families and groups

There are 18 columns.

Columns are vertical on the periodic table.

Elements in the same column have similar physical/chemical properties.

RO

WS

Also called periods

There are 7 rows.

Rows are horizontal on the periodic table.

As you travel across a row, the properties of elements gradually change.

Compounds

• 2 or more elements that have combined in a fixed ratio.

• Can have different properties than the elements that make them up.

• Example – water

Water is different than the elements hydrogen and oxygen.

Molecules

• Smallest particle of a substance with the same properties of that substance

• Diatomic – simplest molecule

• Some elements are naturally diatomic; H, O, Cl

Types of substances created from the periodic table

Mixtures• Combination of 2 or more

substances that have not combined chemically.

• Substances are not combined in the same ratio

• Substances can be broken apart and have their own identity

• Example: A supreme pizza. Every piece has a different ratio of toppings. I can pick them of and each piece is its own entity.

Solutions• Combination of 2 or more

substances that have been combined chemically

• The solution has the same properties throughout

• A solution does not have to be liquid.

• Example: Bronze is a solution. In order to be created a specific ratio of copper and tin must be mixed together. If you look at a piece of bronze, you cannot tell that there are two different elements present.

Types of substances created from the periodic table

ACIDS Produce H+ (as H3O+)

ions in water Produce a negative ion

(-) too • ion – an atom that

has gained or lost an electron

Taste sour Corrode metals React with bases to form

salts and water

BASES

• Produce OH- ions in water

• Taste bitter, chalky

• Are electrolytes

• Feel soapy, slippery

• React with acids to form salts and water

Types of substances created from the periodic table

KNOWLEDGE CHECK

1. Compare a period and a group on the periodic table.

2. Are the properties of Potassium, K, more like those of calcium, Ca, or Sodium, Na?

3. Draw the Ph scale. Label where acids and bases are found.

4. Label the following as a compound, mixture, or solution: a. Waterb. Salt Waterc. Fruit Salad

KNOWLEDGE CHECK

1. Compare a period and a group on the periodic table.Rows are horizontal; groups run vertical.Elements in the same group have similar properties.

2. Are the properties of Potassium, K, more like those of calcium, Ca, or Sodium, Na?

Sodium, Na. Both these elements are in the same group.

3. Draw the Ph scale. Label where acids and bases are found. 1,2,3,4,5,6,7,8,9,10,11,12,13,14 A C I D S B A S E S4. Label the following as a compound, mixture, or solution:

a. Water - Compoundb. Salt Water - Solutionc. Fruit Salad - Mixture