1. +Protons Neutrons -Electrons
Subatomic Particles
+Protons
Neutrons
-Electrons

2. Every pair needs a dry erase board, marker, and paper towel (eraser)
You and your shoulder partner will be answering questions on the dry erase board

3. What DOES AN ATOM LOOK LIKE?
The nucleus has two particles in them: Protons (+) and Neutrons (neutral)
These are electrons. They float in the orbitals. They have a NEGATIVE (-) charge
-We determined through our phet simulation that an atom has 3 particles: proton neutron electron. We also determined that electrons go on the outside, and protons and neutrons are together in the middle.
-Which part of this do you think shows the protons and neutrons? And what do we call the middle part?
Which part of the nucleus do you think is the proton?
The neutron?
What are these rings called? You will hear me referring to them as either orbital or energy levels. They are the same thing
Where are the electrons? What is the charge?
The center of the atom is called the NUCLEUS
These outside rings are called Orbitals, energy levels or electron clouds

4. What else is in an atom?
Besides the subatomic particles, most of the space exists between the orbitals. Therefore, almost all of the atom is made up of EMPTY SPACE!

5. The parts of the Atom Parts of an Atom Particle Charge Relative Mass
Location in Atom
Proton
Positive 1
Nucleus
Neutron
Neutral/No Charge
Electron
Negative
1/1826
Orbitals
What similarities and difference do you notice about this chart?
proton and neutron have the same mass
electron has a different mass (smaller)
charges of each are different
locations differ

6. P
Mass of the particles
The mass of protons and neutrons are almost exactly the same
The mass of an electron is much smaller than either a proton or neutron
It takes almost 2,000 electrons to equal the mass of 1 proton!
SHOW KERNELS

7. Consider this statement…
The nucleus has the most mass of the atom.
Do you agree or disagree?
Why?
What is located in the nucleus?
Protons and neutrons
have almost identical masses
Both are found in the nucleus

8. O The Atomic Number Oxygen 8
Which particle did we determine to give our element its name?
Oxygen 8 O
15.999
The atomic number of Oxygen is 8. This means it has 8 Protons in the Nucleus.
Protons give the element its name. Another way we identify elements is by atomic number. This number tells us how many protons ONLY are located in the nucleus of that atom. So if we ever want to know how many protons a specific element has, we need to locate the atomic number of that element.
Atomic number is ALWAYS Equal to the number of protons in the nucleus

9. The Atomic Mass or Mass Number
The Atomic Mass OR Mass Number: The Atomic mass, or mass number is how much the atom weighs. What part of the atom did we determine contributes to the mass?
The atomic mass of Oxygen can be rounded to 16.
Oxygen 8 O
15.999
The nucleus has the most mass of the atom. Which two particles are contributing to the mass? Protons and neutrons.
If the atomic number tells us how many protons in our atom, how do you think we can figure out the amount of neutrons?? By subtracting mass – atomic number

10. How do we determine the number of electrons?
Just by looking at an element key, can we determine the amount of electrons an atom has?
Oxygen 8 O
15.999
YES! Remember we always want a stable, neutral atom. We determined in our phet simulation that atom becomes neutral when we started adding (and in some cases) taking away electrons. But did you happen to notice how many electrons related to what was in the nucleus?
What you needed to do to make an atom neutral was put the SAME amount of electrons that you did protons.

11. How do we determine the number of electrons?
The number of electrons is EQUAL TO the number of protons
Oxygen 8 O
15.999
Does that mean that the atomic number of an atom is protons + electrons?
NO – remember that atomic number is ONLY protons
JUST USE THE SAME EXACT number to determine electrons

12. But…Why?????? Remember: we WANT to have a neutral atom.
- Charges of protons and electrons
Remember that protons have a positive charge and electrons have a negative charge.
There must be a balance between the positive and negative in order to create a neutral atom.

13. HOW IN THE WORLD AM I SUPPOSED TO REMEMBER ALL OF THIS STUFF, MRS
HOW IN THE WORLD AM I SUPPOSED TO REMEMBER ALL OF THIS STUFF, MRS. JURADO??!?!?!?!

16. Creating Models of the Atom8+
Model the Element Oxygen P+
Oxygen 8 O
15.999 8- E- N
16-8 8

17. Practice Modeling This Atom
Nitrogen 7 N
14.100 E- N

18. MODELING ATOMS LOCATE the atomic number LOCATE mass number
IDENTIFY the number of each subatomic particle.
JUSTIFY how you reached your answer.
Atomic Number
MASS NUMBER

19. Identify this atom Identify how many of each particle.
Can you identify this element based on the information given? - - - + + + + + + - - -

20. LET’S PRACTICE!