THE PERIODIC TABLE

1. THE PERIODIC TABLE

2. History • Mid 1800’s – 70 known elements • Dmitri Mendeleev - 1st to arrange elements systematically & logically • Column by increasing atomic mass • Arranged columns by similar properties • Left blanks (no known element with right mass and properties)

3. Mendeleev’s Periodic Table

4. History cont’d. • 1913 – Henry Moseley (British physicist) determined the atomic numbers of the elements • Periodic Table was rearranged according to atomic numbers. • Current arrangement

6. The Periodic Law Elements have a periodic repetition of their physical and chemical properties when arranged by increasing atomic number.

7. Types of Elements • Metals

8. Metals (characteristics due to the sea of free moving electrons) • Lustrous (shiny) appearance • Malleable & ductile • Conduct heat & electricity • Tend lose e- to form cations • Located on left side of table • Generally solids at room temperature • Mercury – liquid • React with acids (some)

10. Types of Elements • Metals • Nonmetals

11. Nonmetals • Dull appearance • Brittle • Poor conductors of heat & electricity • Tend to gain e- to form anions • Located on right side of table • Hydrogen on the left • Many are gases at room temperature • Do not react with acids

13. Types of Elements • Metals • Nonmetals • Metalloids

14. Metalloids • Lie between metals and nonmetals on the table (stair-step) • Have properties of both metals and non metals • Mainly solids at room temperature

16. Symbol Colors • Natural state at room temperature • Black – solids • Red – gases • Blue (green) – liquids • White – man made elements

17. Table Organization • Rows – periods (1-7)

19. Table Organization • Rows – periods (1-7) • Columns – groups or families • Groups • 1A – 8A • Representative elements • s-block & p-block • 1B – 8B

21. Group Names 1A – Alkali Metals

23. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals

25. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family

27. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family

29. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family 5A – Nitrogen Family

31. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family 5A – Nitrogen Family 6A – Oxygen Family

33. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family 5A – Nitrogen Family 6A – Oxygen Family 7A – Halogens

35. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family 5A – Nitrogen Family 6A – Oxygen Family 7A – Halogens 8A or 0 – Noble Gases

37. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family 5A – Nitrogen Family 6A – Oxygen Family 7A – Halogens 8A or 0 – Noble Gases d-block – Transition Metals

39. Group Names 1A – Alkali Metals 2A – Alkaline Earth Metals 3A – Boron Family 4A – Carbon Family 5A – Nitrogen Family 6A – Oxygen Family 7A – Halogens 8A or 0 – Noble Gases d-block – Transition Metals f-block – Inner Transition Metals Lanthanide series Actinide series

41. Miscellaneous Facts Atomic #’s ≥ 83 are radioactive Seven diatomic elements H2 N2 O2 F2 Cl2 Br2 I2 What are the representative elements? The first 20 elements on the periodic table They form a 7 on the periodic table H2 N2 O2 F2 Cl2 Br2 I2

42. Periodic Trends

43. Periodic Trends Many properties of the elements change in a predictable way as you move through the periodic table These systematic variations are called periodic trends

44. Atomic Radius Distance from center of an atom’s nucleus to its outermost electrons

45. Atomic Radius Trend Down a group Increases as you go down a group Why? Adding another principal energy level where the outermost electrons reside Shielding increases which decreases the effective nuclear charge on the outer electrons Atoms are getting bigger

46. Atomic Radius Trend, cont’d. Across a period (row) Decreases across a row Why? Gain protons as move from left to right (gaining positive charge or increasing effective nuclear charge) Increases the pull on the electrons that are all about the same distance from the nucleus Same principal energy level Shielding is constant for all electrons A stronger attractive force shrinks the electrons’ orbitals and makes the atom smaller

48. Atomic Radius Trend, cont’d.

49. In Your Notes…. Write a definition of atomic radius in your own words What is the group trend? Explain why… What is the period trend? Explain why…. Share your definition, trends and explanations with a partner

50. Ions Atoms that are charged (not neutral) Created by atoms gaining or losing e- Loss of e- - positive ion called a cation Gain of e- - negative ion called an anion No change in # of p+