1. Atomic Structure

2. Atomic Structure: Location: Where it is on the atom
Charge: Electric charge (positive, negative or neutral)
Mass: how big or small it is

3. Parts of the Atom: NUCLEUS
The small center part of the atom that contains the neutrons and protons
from Greek “karyon”, meaning kernel
Protons and neutron are packed very tightly!
The density is the same as having the entire mass of the sun squeezed into Austin!

4. Parts of the Atom: ELECTRON CLOUD
The large region around the nucleus that contain the traveling electrons
100,000 times larger in diameter than the nucleus!
Impossible to determine the exact location of an electron within the cloud.

5. Parts of the Atom: PROTON
Location: the center of the atom
Charge: positive
Mass: About 1 a.m.u, almost 2000 times larger than the electron, slightly smaller than the neutron
PROTON
From Greek “Protos” meaning first
From suffix “ion” meaning subatomic particle

6. Parts of the Atom: NEUTRON
Location: the center of the atom
Charge: neutral
Mass: about 1 a.m.u., almost 2000 times larger than the electron, slightly larger than the proton
NEUTRON
From the noun “neutral”
From suffix “ion” meaning subatomic particle

7. Parts of the Atom: ELECTRON
Location: the outer part of the atom, surrounding the nucleus
Charge: negative
Mass: almost 0 a.m.u., almost 2000 times smaller than the proton and neutron.
ELECTRON
From the word “electric”
From suffix “ion” meaning subatomic particle

8. Comparing Locations:
Electrons are on the outside of the atom. They spin around the nucleus in an electron cloud.
The protons and neutrons are packed tightly together in the center of the atom.
The space between the electron cloud and nucleus is huge!
If the nucleus was the size of a golf ball, the electron cloud would be 1.5 miles away!

9. Comparing Charges:
Electrons have a negative charge, protons have a positive charge and neutrons have no charge.

10. Comparing Mass:
Protons and Nuetrons are almost 2000 times larger than electrons
Electron (so tiny, you can’t see it)
If a proton was the size of the blue sphere on the left, then the electron would be one pixel of the screen—so small, that you can’t see it! Click here to see website showing this.

11. Bohr Model of a HELIUM ATOM+ N -
proton
electron
neutron
Shell
Question: What are some limitations of this model?
Answer: Electrons are too large and not in an electron cloud, electrons are too close to the nucleus.

12. ATOMIC STRUCTURE Particle Charge Mass Location proton (+) charge 1
nucleus
neutron
No charge 1
nucleus
electron
(-) charge
Very small
shell

13. ATOMIC STRUCTURE
Electrons are arranged in Energy Levels or Shells around the nucleus of an atom.
first shell a maximum of 2 electrons
second shell a maximum of 8 electrons
third shell a maximum of 8 electrons

14. Nucleus Contains protons and neutrons
1st shell Can hold up to 2 electrons
2nd shell Can hold up to 8 electrons
3rd shell Can hold up to 8 electrons
Adapted from

15. Be 4 9.012 Beryllium Analyzing Elements on the Periodic Table
Atomic number 4 Be
the number of protons in an atom
Element Symbol
1, 2 or 3 letters. First letter always capitalized, second always lower case.
9.012
Atomic Mass
the number of protons and neutrons in an atom
Beryllium
Element Name
* Number of electrons = number of protons
* Number of neutrons = Atomic Mass (rounded to nearest) – Atomic Number

16. Li So let’s try it…. Lithium How to draw a Lithium atom 3 7
First, look at the Periodic Table
Second, determine the number of protons (Look at the atomic number)
Then determine the number of neutrons (Atomic mass – atomic number)
Then determine the number of electrons
(Look at the atomic number) 3 Li
Lithium 7
Created by G.Baker

17. Li Lithium Protons = 3 3 7 Electrons = 3 Neutrons = 4- + + + - -
Electrons = 3
2 in the 1st shell, 1 in the 2nd shell
Neutrons = 4
(7-3=4)
Created by G.Baker