6.1 PERIODIC TABLE

1. 6.1 PERIODIC TABLE

2. MEYER & MENDELEEV (1869): Showed connection between atomic mass & properties. • Mendeleev – given credit (published first). • Arranged by atomic mass. • Found that properties repeated. • Predicted existence & properties of undiscovered elements. (Ex. Ge) • Recognized discrepancies in properties. (Ex. Te & I)

3. EARLY PERIODIC TABLE

4. MOSELY (1913) – Discovered protons (Atomic #) • Arranged elements by atomic #. • Saw clear pattern of periodic properties (problem of discrepancies solved). • Periodic Law – When elements are arranged by increasing atomic number, there is a periodic repetition of chemical & physical properties.

5. MODERN PERIODIC TABLE:Boxes arranged by increasing atomic # • Groups (families)– vertical columns. • Numbered by “a” & “b” or 1-18 • Elements in the same group share similar properties (Ex. Na & K – both in 1a) • Representative elements (Main Group) • Belong to “a” groups • (“s” & “p” block) • Wide range properties

6. PERIODS - Horizontal RowsShow # Energy Levels • 7 periods on table • Various properties • Ex. Period 3 contains Na, Si, Cl, Ar • (has 3 energy levels)

7. QUIZ • 3) Sodium and magnesium are in the same _____. • 4) Li & Na are in the same _____. • 5) Which 2 elements have the most similar properties? Na Mg K Ar • 1) Mendeleev arranged elements by increasing ______. • 2) How are elements arranged on the modern periodic table?

8. ELEMENT CLASSIFICATION – 3 main types:Metals, Nonmetals, Metalloids • Separated by “zigzag” line • Metals: (Left of zigzag) (except H) • Properties: • Shiny & smooth (when clean) • Ductile (can draw into wire) • Malleable (hammer into sheets) • Good conductors (heat & electricity) • Often react with acids

9. GROUPS OF METALS • 1a (1) = alkali metals • (red) • (not H) • Most reactive metals • (Fr most active) • 2a (2) = alkaline earth metals • (green) • Very reactive

10. TRANSITION ELEMENTS (Metals) “d” block; “b” groups or # 3-12 • Ex. Au, Fe, Cu • Many transition metal compounds are colorful:

11. INNER TRANSITION ELEMENTS (Metals)”f” block, 2 bottom rows (blue) • 1st row (Lanthanide series) (Lanthanoid) • 2nd row (Actinide series) (Actinoid)

12. QUIZ - METALSWHAT GROUP IS THIS? • 8) Representative elements • 1) Group 1a (1) • 2) Group 2a (2) • 3) Cu & Ag are in this group. • 4) Bottom 2 rows are in this group. • 5) Uranium is in this series. • 6) Sm & Ce are in this series. • 7) Most reactive metallic group.

13. NONMETALS – Right of zigzag & HDay 2 • Properties: • Gases or brittle & dullsolids • Only liquid is Br • Poor conductors chlorine gas • Groups: • 6a (16) = chalcogens (oxygen gp.) • 7a = halogens (very reactive) • 8a = noble gases (inert, unreactive, full outer shell)

14. NONMETALS - What group is this? • 1) Group 6a (16) • 2) Group 7a (17) • 3) Group 8a (18) • 4) Hydrogen is the only nonmetal placed with this group. • 5) The most reactive nonmetal group.

15. METALLOIDS (SEMI-METALS)Elements along zigzag (not Al) • Show properties of both metals & nonmetals • Ex. Si & Ge – shiny, semi-conductor, brittle • Used in computer chips, etc.

17. OTHER GROUPS NAMED FOR 1st ELEMENT: • Group 3a (13) Boron group • Group 4a (14) Carbon group • Group 5a (15) Nitrogen group • Groups contain metals, nonmetals & metalloids.

18. QUIZ – METAL, NONMETAL, METALLOID • 2) An element is smooth, shiny, conducts electricity well, & reacts with acid. • Which element is it? W Br As Ge W=metal • 1) Tell whether the following is a metal, nonmetal or metalloid? • Sr Co P Sb Se • m m nm ml nm

19. PROBLEM:Which element is this? • 2) An element is shiny, brittle, partly conducts electricity but does not react with acid. • Zn Ge Kr I • Ge, Group 4A (carbon gp.) • 1) An element is a dull solid, brittle, and does not conduct electricity or react with acid. • Which element & gp.? • Mg Ge S O • S, chalcogens

21. Dmitri Mendeleev1834-1907

22. THE END