Introduction to The Periodic Table

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Introduction toThe Periodic Table
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Why is the Periodic Table important to us?

• The Periodic Table is the most useful tool to a
  chemist.
• You get to use it on every test.
• It organizes lots of information about all the
  known elements.

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Periodic Table
There are 92 naturally occurring elements
arranged by atom size.
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Periodic table
The atoms are arranged by size from smallest (H)
to largest.
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Elements are arranged
Well learn later how this organization works.
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Hydrogen is the smallest atom.

• Hydrogen has an atomic number of 1.
• Hydrogen belongs to a family of its own.

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Reading the Periodic Table
Each box on the Periodic Table stands for 1 of
the elements.
6 C CARBON 12
The atomic number for the element.
The symbol for the element.
The name of the element.
The atomic mass for the element.
If you have no trouble reading the above
information off the Chart, click here to skip the
sample problems.
We can get 4 pieces of information from that box.
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Reading the Table Symbols
Using your Periodic Table, answer these

• What is the chemical symbol for
• Sulfur?
• Neon?

S Ne
Answer all, and then click for the answers.
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Reading the Table Symbols
Using your Periodic Table, answer these

• What elements have these chemical symbols
• Ag?
• Na?

Silver Sodium
Answer all, and then click for the answers.
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Reading the Table Atomic Numbers
Using your Periodic Table, answer these

• What elements have these Atomic Numbers
• 9?
• 56?

Fluorine Barium
Answer all, and then click for the answers.
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Lets Review!

• Every one of these elements is made of the same
  particles.
• A Hydrogen proton is identical to Gold protons.
• What makes atoms different is the number of
  protons.
• The Atomic Number gives us the number of protons.

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Atomic Number

• The Atomic Number gives us the number of protons
  and electrons.

• Helium has an atomic number of 2. How many
  protons does it have?

2. Sodium has an atomic number of 11. How many
electrons does it have?
Use your copy of the Periodic Table for the rest
of this activity.
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11
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Atomic Number

• The Atomic Number gives us the number of protons
  and electrons.

• What element has 15 protons?

2. What element has 92 electrons?
Lets try the same problems in reverse.
Phosphorus
Uranium
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Mass Number

• The Mass Number is the sum of the number of
  protons and the number of neutrons.
• Mass Number Protons Neutrons

What is the mass number of an element that has 17
protons and 18 neutrons? Hint Use the formula
above.
What element is it? Hint Look at the Periodic
Table.
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Chlorine
15
Mass Number

• Many Periodic Tables will use the atomic mass or
  atomic weight instead of the mass number. I know
  it sounds confusing, but they are really the same
  thing as the mass number.

When using these Periodic Tables, you will have
to round the atomic mass off to get the mass
number.
8 O OXYGEN 15.9994
The atomic mass for oxygen is 15.9994.
We round off 15.9994 to 16. Thus 16 is the mass
number of oxygen.
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Finding the Number of Neutrons
The Mass Number is the sum of the number of
protons and the number of neutrons. Mass Number
Protons Neutrons Neutrons Mass Number -
Protons

• How many neutrons does Sulfur have?

2. How many neutrons does Aluminum have?
16
14
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Finding the Number of Neutrons

• If you got those two questions right, click here
  to go to the next slide.
• If you had trouble, click elsewhere on the slide
  to continue.

2. How many neutrons does Aluminum have?
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Step 1 Find the Atomic Number and Mass.
Step 2 Calculate the number of protons.
Step 3 How many neutrons added to 13 would make
27?
Step 3 or what is 27 13?
Atomic Number 13 Atomic Mass - 27
Aluminum has 13 protons because that is the
Atomic Number.
The Answer is14 neutrons.
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Review Questions Begin
Review Question 1

• Which element has the smallest atom?
• Helium
• Hydrogen
• Oxygen
• Nitrogen

Answer Hydrogen (H)
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Review Question 2

• Which element has an atomic number smaller than
  Aluminum?
• Uranium
• Iron (Fe)
• Sodium (Na)
• Chlorine

Answer Sodium (Na)
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Review Question 3

• Which element has an atomic number greater than
  Iron (Fe)?
• Uranium
• Lithium
• Sodium (Na)
• Chlorine

Answer Uranium
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Review Question 4

• Which element has a nucleus with 13 protons?
• Calcium
• Aluminum
• Silicon
• Iron

Answer Aluminum
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Review Question 5
How many protons, electrons, and neutrons does
Hydrogen have?
Answer Protons 1 Electrons 1 Neutrons - 0
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Review Question 6
How many protons, electrons, and neutrons does
Phosphorus have?
Answer Protons 15 Electrons 15 Neutrons - 16
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Review Question 7
How many protons, electrons, and neutrons does
Argon have?
Answer Protons 18 Electrons 18 Neutrons - 22
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Review Question 8
How many protons, electrons, and neutrons does
Uranium have?
Answer Protons 92 Electrons 92 Neutrons -
146
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Go back to the main page, and open the
Constructing an Atom PowerPoint.