The Periodic Table

1. The Periodic Table

3. The Father of the Periodic Table Dimitri Mendeleev was the first scientist to notice the relationship between the elements • Arranged his periodic table by atomic mass • Said properties of unknown elements could be predicted by the properties of elements around the missing element

4. A Correction to the Periodic Table Henry Moseley later discovered that the periodic nature of the elements was associated with atomic number, not atomic mass • The current table is arranged by atomic number.

5. The Periodic Table Column = Group or Family 18 columns on the Periodic Table Row = Period 7 rows on the Periodic Table

6. What does the information in the box tell me? Atomic Number = # of protons # of electrons Elemental Symbol Atomic Mass = # of protons + neutrons 1 H Hydrogen 1.008

7. Organization of the Periodic Table Organized by Atomic Number Metals Non Metals Metalloids Groups (Columns/Families) Periods (Rows)

8. Metals, Nonmetals, and Metalloids Only nonmetal on the metal side Nonmetals are on the right of the stair-step Semi-metals, “metalloids,” touch the stair-step Metals are to the left of the stair- step

9. GROUPS/Family • Each column is called a “group/Family” • Groups have SIMILAR PROPERTIES • Elements in the same group behave in similar ways • The group that an element is in tells you how many valence electrons it has. • This means that they have the same number of electrons in the outermost shell.

10. The Groups of the Periodic Table • Group 1: The Alkali Metals • Most reactive metals on the PT • Rarely found free in nature • Charge of 1 • 1 valence electron • Group 2: The Alkaline Earth Metals • Still quite reactive • Charge of 2 • 2 valence electrons

11. The Groups of the Periodic Table • Groups 3-12: Transition Metals • Found freely and in compounds in nature • Charge is usually 2 but can vary • Usually 2 valence electrons • Group 13: Boron Family • Charge is 3 • 3 valence electrons

12. The Groups of the Periodic Table • Group 14: The Carbon Family • Contains elements that can form unusual bonds (carbon and silicon) • Charge is +4 or -4 • contains 4 valence electrons • Group 15: The Nitrogen Family • Charge is -3 • contains 5 valence electrons

13. The Groups of the Periodic Table • Group 16: The Oxygen Family • Also known as the chalcogens • Charge is -2 • 6 valence electrons • Group 17: The Halogens • Most reactive nonmetals • charge is -1 • 7 valence electrons • Group 18: The Noble Gases (The Inert Gases) • Nonreactive • Charge is 0 • 2 or 8 valence electrons

14. Periods (Rows) The period an element is in indicates how many “shells” it has around it.

15. Special Rows on the PT—Transition Lanthanides Actinides *The Lanthanides & Actinides together are called the Inner Transition Elements.