1. Chapter 5 Preview Lesson Starter Objectives
Mendeleev and Chemical Periodicity
Moseley and the Periodic Law
The Modern Periodic Table

2. Mendeleev and Chemical Periodicity
Section 1 History of the Periodic Table
Chapter 5
Mendeleev and Chemical Periodicity
Mendeleev noticed that when the elements were arranged in order of increasing atomic mass, certain similarities in their chemical properties appeared at regular intervals.
Repeating patterns are referred to as periodic.
Mendeleev created a table in which elements with similar properties were grouped together—a periodic table of the elements.

3. Mendeleev and Chemical Periodicity, continued
Section 1 History of the Periodic Table
Chapter 5
Mendeleev and Chemical Periodicity, continued
After Mendeleev placed all the known elements in his periodic table, several empty spaces were left.
In 1871 Mendeleev predicted the existence and properties of elements that would fill three of the spaces.
By 1886, all three of these elements had been discovered.

4. Properties of Some Elements Predicted By Mendeleev
Section 1 History of the Periodic Table
Chapter 5
Properties of Some Elements Predicted By Mendeleev

5. Moseley and the Periodic Law
Section 1 History of the Periodic Table
Chapter 5
Moseley and the Periodic Law
In 1911, the English scientist Henry Moseley discovered that the elements fit into patterns better when they were arranged according to atomic number, rather than atomic weight.
The Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

6. Periodicity of Atomic Numbers
Section 1 History of the Periodic Table
Chapter 5
Periodicity of Atomic Numbers

7. The Modern Periodic Table
Section 1 History of the Periodic Table
Chapter 5
The Modern Periodic Table
The Periodic Table is an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group.

8. Periodic Table Overview
Section 1 History of the Periodic Table
Chapter 5
Periodic Table Overview
Click below to watch the Visual Concept.
Visual Concept

9. Section 1 Activity Common Properties of Families
Chapter 5
Activity
For each family (alkali earth metal, alkaline metal, halogens, and noble gas) answer the following questions using the internet.
What are three of the elements in this family?
What common properties do these elements share?

10. Periods and Blocks of the Periodic Table, continued
Section 2 Electron Configuration and the Periodic Table
Chapter 5
Periods and Blocks of the Periodic Table, continued
The elements of Group 1 of the periodic table are known as the alkali metals.
lithium, sodium, potassium, rubidium, cesium, and francium
In their pure state, all of the alkali metals have a silvery appearance and are soft enough to cut with a knife.
The elements of Group 2 of the periodic table are called the alkaline-earth metals.
beryllium, magnesium, calcium, strontium, barium, and radium
Group 2 metals are less reactive than the alkali metals, but are still too reactive to be found in nature in pure form.

11. Periods and Blocks of the Periodic Table
Section 2 Electron Configuration and the Periodic Table
Chapter 5
Periods and Blocks of the Periodic Table
Elements are arranged vertically in the periodic table in groups that share similar chemical properties.
Elements are also organized horizontally in rows, or periods.
The length of each period is determined by the number of electrons that can occupy the sublevels being filled in that period.
The periodic table is divided into four blocks, the s, p, d, and f blocks. The name of each block is determined by the electron sublevel being filled in that block.

12. Section 2 Electron Configuration and the Periodic Table
Chapter 5

13. Relationship Between Periodicity and Electron Configurations
Section 2 Electron Configuration and the Periodic Table
Chapter 5
Relationship Between Periodicity and Electron Configurations

14. Order of Filling Electrons
Starting from the top right, draw arrows diagonally. This is the order that electrons are filled

15. Recall:
For each orbital type (s, p, d, f) a different number of electrons can be held
s orbital: 2 electrons
p orbital: 6 electrons
d orbital: 10 electrons
f orbital: 14 electrons

16. Section 2 Electron Configuration and the Periodic Table
Chapter 5

17. Writing Electron Configurations
Steps:
Count the number of electrons the atom has
Follow the filling order on the previous slide (1s, 2s, 2p, 3s…)
Be sure to indicate how many electrons are in each orbital with a superscript number (1s2, 3p6, etc.)

18. Example
Electron configuration of phosphorus (15):
1s22s22p63s23p3
Electron configuration of germanium (32):
1s22s22p63s23p64s23d104p2
Practice: Complete the electron configuration for Nitrogen, Sodium and Iron

19. A MUCH simpler way
As you can imagine, doing this for elements with atomic numbers such as 75 or 83 is going to be extremely time consuming
Thankfully, we can use Nobel Gas Notation to provide electron configurations.

20. Nobel Gas Notation To use Nobel Gas notation, follow these steps:
Find the element on the periodic table
Write down the Nobel gas from the row above in square brackets
Complete the electron configuration from after the Nobel gas
Example: Germanium has an electron configuration of: 1s22s22p63s23p64s23d104p2
Nobel Gas notation: [Ar]4s23d104p2

21. Nobel Gas Notation Practice Questions:
Write the Nobel Gas notation electron configuration for the following elements
Calcium
Arsenic
Silver