1. Atomic Structure

2. Atoms An element is a species that is made of only 1 type of atom.
Smallest particle of an element that has the properties of that element.
Too small to be seen, even by strong microscopes.

3. Basic Building Blocks of Atoms
Protons
Positively charged particle located in the nucleus.
Has a relative mass of 1
Neutrons
Neutral particle located in the nucleus
Electrons
Negatively charged particle located outside the nucleus.
Has a relative mass of 1/1836

4. Inside Atoms

5. C Periodic Table Cells 6 Carbon 12.011 Atomic Number Atomic Symbol
Atomic Mass

6. Definitions Atomic Number Average Atomic Mass Atomic Mass Number
Number of Protons in the nucleus. Essentially equivalent to the elements Social Security Number
This number defines what the element is. No two elements have the same atomic number
Average Atomic Mass
Average mass of all the different types (Isotopes) of a single element
The decimal number on the periodic table.
Atomic Mass Number
Sum of the number of protons and neutrons of a specific atom.
Number cannot be a decimal number!!!!!

7. Isotopes Carbon has an weighted mass of 12.011.
How is it possible to have .011 protons or neutrons….It isn’t
Many elements have multiple different isotopes
Isotopes are species of the SAME ELEMENT that have different numbers of neutrons

8. Isotopes
Atoms with the same number of protons, but different numbers of neutrons.
Atoms of the same element (same atomic number) with different mass numbers
Isotopes of chlorine
35Cl 37Cl
chlorine chlorine - 37

9. How to figure out how many P+, No, and e- are in an atom
Atomic # = the number of protons
Atomic Mass # = protons + neutrons
For any atom, the atomic # also tells how many electrons there are.

10. Ex: How many protons, neutrons and electrons are in U-236.
On the Periodic Table, Uranium has an atomic number of 92.
The -236 Tells us how much that specific uranium species weighs.
P+ = atomic number = 92
No = Mass # - atomic # = = 144
E- = atomic number = 92

11. Example Problem How many proton are in the following atom?
Atomic Mass Number = 64
Number of Neutrons = 35
Number of Protons = ???

12. Example Problem Solved
How many proton are in the following atom?
Atomic Mass Number = 64
Number of Neutrons = 35
Number of Protons = ???
Protons + Neutrons = Mass Number
(X) = 64
64-35 = X
X= 29

13. Isotopes
Atoms with the same number of protons, but different numbers of neutrons.
Atoms of the same element (same atomic number) with different mass numbers
Isotopes of chlorine
35Cl 37Cl
chlorine chlorine - 37

14. Ions An ion is an atom that has lost or gained one or more electrons.
To determine the number of electrons, you must know the ion’s charge.
For every (+) , you subtract an electron
For every (-) , you add an electron.
Charge = #P+ - #e-

15. Example
Oxygen most often has a charge of (-2) when it becomes an ion. How many electrons does an oxygen ion have?
Charge = (-2), so….
-2 = 6 -X
-2 - (6) = -X
-8 = -X
8 = X

16. Fill out this Chart Element Atomic # Mass # Charge # Protons
# Neutrons
# Electrons
Phosphorous 15 16
Zinc 66
Sodium 22 +1
Plutonium 94
244

17. Fill out this Chart Element Atomic # Mass # Charge # Protons
# Neutrons
# Electrons
Phosphorous 15 31 16
Zinc 30 66 36
Sodium 11 23 +1 12 10
Plutonium 94
244
150