OBJECTIVE: DESCRIBE THE GENERAL STRUCTURE OF THE ATOM, AND EXPLAIN HOW THE PROPERTIES OF THE FIRST 20 ELEMENTS IN THE PERIODIC

TABLE ARE RELATED TO THEIR ATOMIC STRUCTURES

Atomic Structure

Brainstorm

What is matter? Give at least three examples. Give two examples of

things that are NOT matter, (Hint: thoughts).

What is mass? What is an atom?

Give at least three examples of things in this room that are made of atoms.

Is the air we breathe made of atoms? Explain your answer.

What is a scientific theory?

The Basics

Matter: Anything that takes up space and has a mass. Examples: a desk, a person, oxygen Non Examples: feelings, thoughts

Mass: A measure of how much matter an object contains. Mass is related to weight.

Element: A substance that can not be broken down into a more simple substance. Example: Gold, Oxygen, Carbon, Helium, Iron

The Basics

Compound: A substance made of two or more elements. Example: CO2 , H2O

Theory: A tested explanation with supporting evidence. Can be changed, revised or disproved. Example: Theory of Evolution-The change in physical

traits in a population over long periods of time.

Discussion

Can scientist be proven wrong? Can science theories be changed?Is science a process that is continually

worked on or is it set in stone? Do many people usually contribute science

knowledge?

Activity

Discovering the Atom

Aristotle: Greek Philosopher 322 BC-384BC Believed that four

elements made up all things

Discovering the Atom: Dalton’s Contribution

John Dalton England 1776 Science Teacher Atom looked like a ball

Theory: All matter is made up of individual particles called atoms, which cannot be divided.

Discovering the Atom: J.J. Thomas

J.J. Thomas 1800 Discovered the

electron Plum pudding model

Discovering the Atom: Ernest Rutherford

Rutherford: 1900 New Zealand Discovered protons

and nucleus Electrons move

randomly in space

Discovering the Atom: Niels Bohr

Bohr: 1913 Electrons move in

fixed orbit around nucleus

Discovering the Atom: Schrodinger and Chadwick

Erwin Schrodinger: 1926 Describes motions of

electrons Leads to electron

cloud theory James Chadwick

1932 Confirms the existence

of neutrons Nucleus contains

neutrons and protons

The Atom – “Uncut” or “Indivisible”

The smallest part or unit of an element.

Cannot be broken down without losing its properties

Basic building block of matter

Makes up all physical things

Parts of the Atom

1. Protons Positively charged sub-

atomic particle Found in the nucleus

2. Neutrons Neutrally or no charge Subatomic particle found

in the nucleus 3. Electrons

Negative charge Subatomic particle found

outside of nucleus Nucleus

Dense center of the atom Positive charge

Atomic Number

The number of protons for any given element All element of one kind

have the same number of protons Example: All Hydrogen (H)

atoms have just one proton Atoms of different

elements have different number of protons

Atomic number also gives us the number of electrons

Discuss

What charge are protons?What charge are electrons?Why do you think atoms have the same

number of protons and electrons?

Neutral Atoms

The positive protons and negative neutrons balance out.

This make the charge of an atom neutral or zero.

Draw an Example

Mass Number

The number of protons and neutrons found in the nucleus Protons + Neutrons =

Mass Number Example: Carbon has a

mass number of 12

This means there are 6 protons and 6 neutrons

*Do the math

Practice Calculating the Number of Neutrons

Periodic Table

Bohr Model

Looks like the solar system

Contains different energy levels

General Example:

Energy Levels and Orbitals

Each ring of the Bohr Model is an energy level

As you go further out from the nucleus the energy of the electron becomes greater

Electrons orbit around the nucleus much like the earth orbits around the sun

Electron Configuration

Configuration = Arrangement Desks in the classroom are arranged in a

specific wayElectrons are found in orbits around the

nucleus. This is their “electron configuration”

Energy Levels and Orbits

Energy level 1 Can contain only two electrons

Energy levels 2 and 3 Can contain up to eight electrons

Energy levels must be filled before electrons can move to the next shell

*Draw example labeling energy levels