B1: CLASSIFYING MATTER

B1-1: WHAT ARE ELEMENTS?

I. BUILDING BLOCKS OF MATTER

Matter is everything that takes up space and has matter.

Matter can be found in: The food we eat The water we drink The air we breathe

Matter may feel different, have different smells, or may appear differently

As a matter of fact, there are over 100 substances in our world!

I. BUILDING BLOCKS OF MATTER

Elements Substances that cannot be broken down into other

substances by heat, light, or electricity. Examples: Iron, Gold, Oxygen

Why are they “Building Blocks”? Each element is like a letter of the alphabet. Different combinations make-up different substances

found in our world.

I. BUILDING BLOCKS OF MATTER

Gold Aluminum

I. BUILDING BLOCKS OF MATTER

Sulfur Oxygen

I. BUILDING BLOCKS OF MATTER

Aristotle Believed matter to made of four basic substances:

Earth, Air, Fire, and Water

He thought that all other substances were made of a combination of the four basics.

Ancient peoples often used elements such as gold, silver, and mercury without realizing they were elements.

I. BUILDING BLOCKS OF MATTER

Scientists had been trying to identify all the “building blocks of matter” for hundreds of years.

Scientists often experimented with hundreds of substances as they searched for new elements.

They broke down common substances, such as salt, into their basic parts. (Proof that salt was not an element!)

I. BUILDING BLOCKS OF MATTER

With all the work of scientists, you may ask the question, “How do we classify these elements?”

Elements are grouped by their common properties and characteristics.

These groups are: Metals Nonmetals

I. BUILDING BLOCKS OF MATTER

Metal Characteristics include:

Shiny Thermal

conduction(heat) Electricity Malleability (Change

shape) Example:

Copper Iron Gold

I. BUILDING BLOCKS OF MATTER

Nonmetal Not shiny Heat and electricity to

not pass through easily

Malleability limited Examples:

Oxygen Carbon Sulfur

II. THE PERIODIC TABLE

Scientists tried to classify and arrange the elements into easy-to-read charts.

In 1869, Dmitri Mendeleev discovered that by arranging elements by the masses, the order came very naturally.

He also arranged the element by their unique properties in rows and columns.

Once he found where each known element should be placed, he left space for elements to be discovered later.

II. THE PERIODIC TABLE

II. THE PERIODIC TABLE

Each element on the table has information to distinguish it for every other element.

These parts include: The Element’s name The Element’s symbol The Element’s number

II. THE PERIODIC TABLE

Let’s examine the period table on p. B12-B13. Let’s find:

Hydrogen Silver Uranium Neon Aluminum Potassium

III. ATOMS

The structure of an Atom: Atom: The smallest particle of an element that has the

properties of the element Nucleus: The center of an atom, where protons and

neutrons are located Proton: A particle in an atom that has a positive

electrical charge (+) Neutron: A particle in an atom that has no charge Electron: A particle in an atom that has a negative

electrical charge (-) On the board, copy down the hydrogen atom

diagram.

III. ATOMS

All atoms of an element have a particular number of protons.

The element’s number in the periodic table depends upon the number of protons found in the nucleus. Oxygen-Atomic Number 8 = 8 protons Gold- Atomic Number 79 = 79 protons

III. ATOMS

Elements have the same number of electrons as protons.

Elements can have different numbers of neutrons, because they have no charge!!!