Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Periodic Table Chapter 19 Section 3.

Similar presentations

Presentation on theme: "The Periodic Table Chapter 19 Section 3."— Presentation transcript:

1 The Periodic Table Chapter 19 Section 3

2 Organizing the Elements
In the late 1800s, Dmitri Mendeleev searched for a way to organize the elements His first arrangement was done by increasing atomic masses Found a pattern Chemical properties in lighter elements were repeating in heavier elements The pattern was Periodic The arrangement is now known as the periodic table Mendeleev’s table was so well constructed that he was able to predict the location of elements that had not yet been discovered.

3 Improving the Periodic Table
Mendeleev’s table was arranged by atomic mass But there were some spots were atomic mass placement and atomic properties didn’t make sense Cobalt and Nickel In 1913, Henry Moseley proposed a table arranged by increasing atomic number This change corrected the problems found in Mendeleev’s table Moseley’s arrangement is the one used in the modern table of elements

4 The Atom and the Periodic Table
The vertical columns of the periodic table are known as groups The atoms of elements found in the same family have similar properties This is due to the number of electrons in the outer energy level

5 Electron Cloud Structure
Electrons in the electron cloud have different energies The differences are modeled by placing them in energy levels. Low energy Close to the nucleus High energy Further away from the nucleus Labeled from 1 to 7 Energy level 1 can hold up to two electrons Energy level 2 can hold up to 8 electron Energy level 3 can hold up to 18 electrons A complete and stable outer energy level will have 8 electrons Sooo…elements in the same column have the same number of electrons in the outer energy level

6 Rows on the Table As you go across the table, an electron is added to the outer shell and one proton is added to the nucleus The row tells you with energy level the outer most electrons are located in The rows are called periods

7 Electron Dot Diagrams Electron dot diagrams were introduced by G.N Lewis They are a short hand way of showing how many electrons are in the outer energy level They are also used to show how atoms combine to form compounds Electron dot diagrams will be the same for all elements in a column

8 Regions on the Periodic Table

Download ppt "The Periodic Table Chapter 19 Section 3."

Similar presentations

Ads by Google