1. The Periodic Table of the Elements

2. Connecting the Atom to Elements ● The different types of atoms make up the 100 different elements that are known to man. ● What are those 100 elements? ● The element song: Tom Lehrer

3. Inside the Squares on the Table Look at the Periodic Table on pg. 80-81. Shows all elements in the entire world!

4. Dmitri Mendeleev ● In the 1800s, scientists began to believe the elements could be organized in a useful way ● A scientist named Mendeleev began observing the elements and noticed that some elements shared similar characteristics ● Began organizing all of the elements

5. The Periodic Table ● Mendeleev created the first Periodic Table in 1869 ● Periodic means “a regular repeated pattern” ● The properties of the elements repeat themselves in how they are arranged on the periodic table

6. Patterns in the Periodic Table How the table is organized: Look at the periodic table. Talk with your partner. What patterns do you notice about how it is arranged? Write them down!!

7. Patterns in the Periodic Table 1. atomic mass (the mass of one atom of the element) Hydrogen has smallest atomic mass Mendeleev began to notice more patterns when he arranged the elements by their atomic mass

8. Patterns in the Periodic Table ● Today, the periodic table is arranged by atomic number ● Atomic number- the number of protons in the nucleus – Every element has a different number of protons in its nucleus!!!

9. Patterns in the Periodic Table Arranged into columns and rows The columns are called groups (or families) - the groups have similar characteristics The rows are called periods - the elements will gradually change properties as you move across the rows

10. One More Pattern Remember the atom??? Remember the parts of the atom??? The electrons determine whether or not a element with bond (or connect) to other types of elements The electrons are at different distances from the nucleus

11. continued... ● The electrons that are furthest away can be shared or transferred to other atoms ● Valence electrons- electrons that are involved in transfer or sharing ● Elements have different numbers of valence electrons. These electrons will increase from left to right across a period

12. The Periodic Table