1. Particles in an atom
Recall in Junior Cert

2. Sort it out! How would you sort out the following cards?
What are your reasons for the method your group have chosen?

4. Elements – different types of atom
Boardworks Science for Scotland: S1 and S2
Atoms
Elements – different types of atom
Elements are the simplest substances. There are about 100 different elements.
Where can we find these elements?
Each element is made up of very tiny particles called atoms, and each element is made up of just one particular type of atom, which is different to the atoms in any other element.
Gold is an element made up of only gold atoms.
Photo credit (top): Marja Flick-Buijs
Gold wedding rings.
Photo credit (bottom): Gaston Thauvin
Charcoal used for drawing.
Carbon is an element made up of only carbon atoms.

5. Atoms – the building blocks
Boardworks Science for Scotland: S1 and S2
Atoms
Atoms – the building blocks
John Dalton had the first ideas about the existence of atoms over 200 years ago.
However, it is only relatively recently that special microscopes (called electron microscopes) have been invented that can actually ‘see’ atoms.
Electron microscopes produce images similar to this one. What could it be showing?
The grey blobs are individual lead atoms.

6. Boardworks Science for Scotland: S1 and S2 Atoms
How small is an atom?
Atoms are very small – they are about cm wide.
Think about the thickness of a crisp.
The number of atoms you would need to stack up to make the thickness of a crisp, is approximately the same number of crisps you would need to stack up to make the height of Mount Everest!
That’s roughly 7 million crisps!

7. Use the Zoom in the next slide

8. Boardworks Science for Scotland: S1 and S2 Atoms
What are atoms made of?
Teacher notes
This interactive zoom activity shows students the structure of diamond down to the nuclear level. It also shows the relative sizes of each stage.

9. What particles are atoms made of?
Boardworks Science for Scotland: S1 and S2
Atoms
What particles are atoms made of?
For some time, people thought that atoms were the smallest particles and could not be broken into anything smaller.
Scientists now know that atoms are actually made from even smaller particles. There are three types:
proton
neutron
electron
How are these particles arranged inside the atom?

10. What is the structure of an atom?
Boardworks Science for Scotland: S1 and S2
Atoms
What is the structure of an atom?
Protons, neutrons and electrons are not evenly distributed in an atom.
The protons and neutrons exist in a dense core at the centre of the atom. This is called the nucleus.
The electrons are spread out around the edge of the atom. They orbit the nucleus in layers called shells.

11. Let´s act it out!

12. Boardworks Science for Scotland: S1 and S2 Atoms
Labelling the atom
Teacher notes
This drag and drop activity provides the opportunity for informal assessment of students’ understanding of the structure of the atom.

13. Mass and electrical charge
Boardworks Science for Scotland: S1 and S2
Atoms
Mass and electrical charge
There are two properties of protons, neutrons and electrons that are especially important:
mass
electrical charge.
Particle
Mass
Charge
proton 1 +1
neutron 1
electron
almost 0 -1
The atoms of an element contain equal numbers of protons and electrons and so have no overall charge.

14. ATOMIC COMPOSITION Protons (p+) Electrons (e-) Neutrons (no)
+ electrical charge
mass = x g
relative mass = atomic mass units (amu) but we can round to 1
Electrons (e-)
negative electrical charge
relative mass = amu but we can round to 0
Neutrons (no)
no electrical charge
mass = amu but we can round to 1

15. Properties of the particles of the atom
Boardworks Science for Scotland: S1 and S2
Atoms
Properties of the particles of the atom
Teacher notes
This drag and drop activity provides the opportunity for informal assessment of students’ understanding of the properties of protons, neutrons and electrons. Appropriately coloured voting cards could be used with this activity to increase class participation.

16. Seriously..how cool are atoms!
Because all electrons have negative charges, and negatives repulse negatives , at a subatomic level we actually never touch anything!
An electron exists in many points around the atom simultaneously
For each subatomic particle there is an equivalent "antiparticle". That's right! There is such a thing as antimatter in the real world. If matter and antimatter collide, both are annihilated
It's possible that atoms do not strictly exist when you're not looking at them
You can change the properties of atoms today, after you lose them tomorrow. Retroactively. How atoms behave now depends as much on what you do tomorrow as on what you do now

17. Putting atoms together
Have a look at your Periodic table…
We will study the actual elements later BUT
Check out all the numbers!!

18. Atomic Number, Z
All atoms of the same element have the same number of protons in the nucleus, Z 13
Atomic number Al
Atom symbol
26.981
AVERAGE Atomic Mass

19. Mass Number, A Mass Number (A) = # protons + # neutrons
C atom with 6 protons and 6 neutrons is the mass standard
= 12 atomic mass units
Mass Number (A) = # protons + # neutrons
NOT on the periodic table…(it is the AVERAGE atomic mass on the table)
A boron atom can have A = 5 p n = 10 amu

20. Atomic Symbols sodium-23
Show the name of the element, a hyphen, and the mass number in hyphen notation
sodium-23
Show the mass number and atomic number in nuclear symbol form
mass number
23 Na
atomic number

21. Counting Protons, Neutrons, and Electrons
Protons: Atomic Number (from periodic table)
Neutrons: Mass Number minus the number of protons (mass number is protons and neutrons because the mass of electrons is negligible)
Electrons:
If it’s an atom, the protons and electrons must be the SAME so that it is has a net charge of zero (equal numbers of + and -)

22. Let´s practice Using your play-doh to make the molecular model for:
Boron
P: 5 N: 6 E: 5
Helium
P: 2 N: 2 E: 2
Lithium
P: 3 N: 4 E: 3