1. 1.1 Atomic Structure Objectives 1; 2

2. Essential Questions What is an atom?
What is atomic # and how do you determine it?
How is atomic # to the identify an element?
What is mass # and how do you determine it?
What is the difference between atomic mass and mass number?
What is an isotope?
How do you determine the number of protons, neutrons, and electrons for an isotope?

3. Elements and Atoms
An element is the smallest particle of matter that retains its chemical identity
We use symbols for the names of elements
1 or 2 letters, the first letter always is Capital and the second is lowercase
An atom is the smallest particle of an element that retains its identity in a chemical reaction.

4. Parts of the Atom
There are three subatomic particles that make up atoms: proton, neutron, and electron
Protons are positively charged particles found in the nucleus
Neutrons are neutral particles found in the nucleus
Electrons are negative particles found in orbitals around the nucleus

5. Part of the Atom Subatomic Particle Symbol Relative Charge
Location in Atom
Relative Mass (amu)
Proton
 p+
 1+
Nucleus 1
Neutron
 n0
Electron
 e- 1-
Orbitals

6. Atomic Number Atomic number is the number of protons.
How do you find the atomic number?
Periodic table
How do we use atomic number?
Identifies the type of element because each element has its own unique atomic number
The atomic number of a neutral atom is equal to number of electrons

7. Mass Number
Mass number is the total number of protons and neutrons in an atom (mass number = # of protons + # of neutrons)
Mass number can be used to find the number of neutrons
# of neutrons = Mass number - # of protons

8. Symbol Notation There are two way of doing symbol notation.
Mass Number (A), Atomic Number (Z), and element symbol (X)
Element name – mass number

9. Isotopes
Isotopes are atoms of the same element that have different mass numbers
Carbon – 14 and carbon – 12
The protons and electrons (if neutral) will be the same for isotopes of the same element
The neutrons and mass number will be different for isotopes of the same element

10. Isotopes (cont)
Element
Proton
Neutron
Electron 1 26 30 2 25 3 27 32 4 29
Which of the above would be isotopes of the same element?
Which would have the same mass number?
1 and 4
2 and 4

11. Atomic Mass
The atomic mass is an average mass based off of the abundance and mass of the different isotopes and is found on the periodic table.
amu – atomic mass unit
When the atomic mass is rounded to the nearest whole number that is the most common isotope of the element
Tc atomic mass is 97.9 so a mass number of 98 is the most common isotope

12. Protons, Neutrons, and Electrons
Determine the number of p, n, and e-
Cobalt – 58
Barium – 138
204Tl
227Ac
In (round the mass to the most common isotope)
Yttrium

13. Protons, Neutrons, and Electrons (cont)
Fill in the following chart
Element Shorthand
(AX)
Atomic #
Protons
Neutrons
Electrons
Mass #
159Tb
159 46 60 87
223
116 77 12 24

14. Protons, Neutrons, and Electrons (cont)
Answer Key
Element Shorthand
(AX)
Atomic #
Protons
Neutrons
Electrons
Mass #
159Tb 65 94
159
106Pd 46 60
106
223Fr 87
136
223
193Ir 77
116
193
24Mg 12 24

15. Protons, Neutrons, and Electrons (cont)
Fill in the following chart
 Element
Osmium-191
Osmium-190
Protons
Neutrons
Electrons
 Element
Protons
 57
Neutrons
 81
 83
Electrons

16. Protons, Neutrons, and Electrons (cont)
Answer Key
 Element
Osmium-191
Osmium-190
Protons
 76 76
Neutrons
115
 114
Electrons
 Element
Lanthanum-138
Lanthanum-140
Protons
 57
Neutrons
 81
 83
Electrons 57

17. Essential Questions What is an atom?
What is atomic # and how do you determine it?
How is atomic # to the identify an element?
What is mass # and how do you determine it?
What is the difference between atomic mass and mass number?
What is an isotope?
How do you determine the number of protons, neutrons, and electrons for an isotope?

18. 1.1 Tracked Assignment
1.1 Tracked Assignment Worksheet