The Periodic table

1. The Periodic table Ch. 5 sec. 1

2. Dmitri Mendeleev • Russian chemist, discovered a pattern to the elements in 1869. • elements were arranged in order of increasing atomic mass, those that had similar properties occurred in a repeating pattern.

3. Periodic • Periodic table of elements • Describe something that occurs or repeats at regular intervals • Elements properties repeated every 7 elements

4. Periodic law • Repeating chemical and physical properties of elements change periodically with atoms atomic number

5. The Periodic Table and Classes of Elements • Metals • Elements are classified as metals, nonmetals, and metalloids, according to their properties • Atoms of most metals have few electrons in their outer energy level. Most metals are solid at room temperature.

6. Metals Cont. • Nonmetals • Most elements are metals. Metals are found to the left of the zigzag line • Nonmetals are found to the right of the zigzag .Atoms of most nonmetals have an almost complete set of electrons in their outer level.

7. Metalloids • also called semiconductors, are the elements that border the zigzag. Atoms of metalloids have about half of a complete set of electrons in their outer energy level.

8. Decoding the Periodic Table • element’s name, chemical symbol, atomic number, and atomic mass. • chemical symbols are the same worldwide • Rows Are Called Periods • physical and chemical properties of elements in a row follow a repeating pattern • Columns Are Called Groups or Family • similar chemical and physical properties