Structure of the Atom 2-1

Structure of the Atom

Do Quickly #7

A switch is inserted into a series circuit of Christmas lights. During the night, the switch is left open. The lights will...

A. continue to burn
B. be turned off
C. become a parallel circuit
D. burn brighter

We will know we have it when we can build an example of an atom and answer questions concerning its structure.

Success Criteria

Today we will learn about atomic theory and the structure of the atom so we can understand the makeup of matter and how to read & understand the periodic table.

Learning Target

Structure of the Atom

​S8P1. Obtain, evaluate, and communicate information about the structure and properties of matter.

Multiple Choice

What is an atom?

• the smallest unit of matter

• a type of liquid

• a type of solid

• a type of gas

Multiple Choice

Who is credited with proposing the first atomic theory?

• Maharishi Kannada

• Auntie

• Sage Khanna

• Democritus

Multiple Choice

What is the center of the atom?

• neutrons

• protons

• electrons

• nucleus

Multiple Choice

What is the electron cloud?

• a type of gas cloud

• a representation of the unpredictable nature of electrons

• a cloud made of electrons

• a cloud made of protons

Multiple Choice

What percentage of the atom is empty space?

• 10%

• 99.9%

• 50%

• 25%

In this section of our Matter Unit, we will be learning about the elements on the periodic table; however, in order to do this we must first understand atomic structure first.

​

The Periodic Table

Atom - the smallest particle of an element that still has the properties of that element.

REMEMBER: An element is the simplest form of matter.

​

The ATOM

- first to name the atom
- atomus means indivisible in Greek and he believed there was nothing smaller

​​400 BC
Democritus

- atom is solid sphere that can't get any smaller
- elements are made of atoms that all have the same mass and compounds are atoms of different elements combined

​​1803
John Dalton

- developed the first periodic table

​​1869
Dmitri Mendeleev

Plum Pudding Model
- the atom is divisible
- It is positively charged sphere with negative particles embedded throughout

​​1904
JJ Thomson

​The Discovery of the Atomic Structure

Nuclear Model
- Gold foil experiment
- The mass of the atom & its protons were in the nucleus, with low mass electrons surrounding it

​​1911
Ernest Rutherford

​- the number of protons is unique to each element (atomic number) and arranged this way on the periodic table

​​1913
Henry Mosely

Bohr Model
- electrons are negative particles in fixed orbits around a positively charged nucleus

1913
Niels Bohr

​Electron Cloud Model
- electrons are divided into shells and do not move in fixed orbits

​​1926
Schrodinger & Heisenberg

​The Discovery of the Atomic Structure

Two parts of the atom:
1. Nucleus
- Dense center
- Made of protons and neutrons
- Positively charged
- Where the mass of the atom is located
2. Electron Cloud
- Space surrounding the nucleus
- Broken down into regions called "shells" or "energy levels"
*Shells farthest from the nucleus have the most energy
*Electrons in the outermost energy level are called
valence electrons.
- Negatively charged
- Where the volume of the atom is located

Atomic Structure

positive particle in the nucleus

Proton
p⁺

neutral particle in the nucleus with protons

Neutron
n⁰

negative particle outside of the nucleus in the electron cloud

Electron
e^-

Subatomic Particles​

What holds it together?

FORCES
- Attractive force between the nucleus (+) and the electron cloud (-)
Opposites attract - this attraction holds it all together
- Repulsive force between (-) electrons
Electrons want to be as far apart as possible which creates volume
- Repulsive force between (+) protons
Energy holds the nucleus together; Protons want to be as far apart
as possible

• Proton

• Neutron

• Electron

​

Let's Build an Atom

Success Criteria

We will know we have it when we can build an example of an atom and answer questions concerning its structure.

Match

Match the following

• The smallest particle of an element that still has the element's properties

• The subatomic particle is what gives the nucleus an overall positive charge

• This space surrounding the nucleus that has an overall negative charge

• Located in the outermost energy level of the electron cloud, with the most energy

• This subatomic particle contributes to the overall mass but not its charge

Atom

Proton

Electron Cloud

Valence Electron

Neutron

• Atom

• Proton

• Electron Cloud

• Valence Electron

• Neutron

Success Criteria

We will know we have it when we can build an example of an atom and answer questions concerning its structure.

Match

Match the following

• The dense center of the atom

• The smallest known particles that make up both protons and neutrons

• Also known as energy levels

• The subatomic particle located in the space surrounding the nucleus

Nucleus

Quarks

Shells

Electrons

• Nucleus

• Quarks

• Shells

• Electrons

Labelling

Label the parts of the atom

Drag labels to their correct position on the image

Electron

Nucleus

Electron Cloud

Neutron

Proton