1. 2.4 Structure of the Atom
Science 8 Name:________________ Date:_________________ Block:____

2. An atom is made up of electrons, neutrons, and protons.
Atom: the smallest particle of an element that retains the properties of that element
All matter is made up of atoms
Atoms are made up of subatomic particles
atom: the smallest particle of an element that retains the properties of that element

3. Structure of the Atom
What do you remember about the structure of the atom? List at least 4 points
__________________________________________

4. The Atom: Nucleus Nucleus Tiny region at the centre of the atom
The nucleus makes up almost 100% of the mass of the atom.
Most hydrogen atoms: contain one proton
All other atoms: contain both protons and neutrons
Number of protons determines charge of the nucleus and the identity of an atom

5. The Atom: Electron Energy Shell
The region that electrons occupy accounts for over % of an atom’s volume
Electrons occupy specific regions (energy levels) that surround the nucleus
Electrons are like a spread- out cloud of negative charge that exists in the whole region at once
Electrons can jump to higher energy levels by absorbing energy or lower energy levels by losing energy

6. Electrons Electrons jumping to higher
Energy absorbed
Energy Released
Electrons jumping to higher
energy level, by absorbing energy
Electrons jumping to a lower energy level and releases energy

7. The Atom: Electric Charge
Comes in two types: positive and negative
Protons: positive charge (1+ each)
Electrons: negative charge (1– each)
Neutrons: no charge
Like charges REPEL one another. Provide an example. ,
Opposite charges ATTRACT one another. Provide an example. +-
The overall charge of an atom is 0
In an atom:
the number of protons = the number of electrons

8. The Nucleus: Electric Charge
What subatomic particles are found inside the nucleus?
Proton and neutrons
Protons have a positive charge
Neutrons have no charge
We just learned that like charges REPEL one another
Yet the nucleus has not explode. Why?
There is a STRONG FORCE also known as NUCLEAR FORCE that holds the nucleus together
This force is very strong across very short distances
It counteracts the repulsion between protons so that the protons in the nucleus does not fly apart.
Neutrons between the protons also help stabilize the nucleus.

9. Protons and Neutrons are made of elementary particles
Protons and Neutrons are made up of elementary particles called quarks
The quarks are bonded together by gluons (kind of like glue)
2 up quarks
1 down quark
gluon

10. Periodic Table Song: https://www.youtube.com/watch?v=VgVQKCcfwnU
The Periodic Table

11. Origin of the Periodic Table
There are many different elements that exist on earth.
Chemists wanted to find a way to organize and group all the different elements on earth
In 1867, Dimitri Mendeleev found patterns in the elements and organized them into a table.
He organized elements based on their atomic number (the number of protons)
Elements are characterized by their atomic number
This became known as the periodic table
The resulting table had a few empty spots.
These “empty spots” are elements that have not been discovered yet.

12. Origin of the Periodic Table
Take a look at your periodic table
Do you see a pattern based on atomic number?

13. Periodic Table Name – Titanium Symbol – Ti4
Periodic Table 5 2 1 3
Name – Titanium
Symbol – Ti
Average Atomic Mass – mass of the AVERAGE atom – 47.9
Atomic number – number of protons – 22 (Notice how the pattern increases one by one throughout the periodic table)
Ion Charges – 4+, 3+

14. Practice What is the overall charge of an atom?
What relationship do the number of protons and the number of electrons have in an atom?
An atom is neutral
The number of protons = the number of electrons

15. Practice K B Name Atomic number Average Atomic mass Number of protons
Name
Atomic number
Average Atomic mass
Number of protons
Number of electrons 19 K
Potassium
39.1 5 B
Boron
10.8
Potassium
Boron 19 5
39.1
10.8 19 5 19 5