Chapter 5: The Periodic Table

1. Chapter 5: The Periodic Table 5-1 Development of the Periodic Table 5-2 Reading the Periodic Table 5-3 Periodic Trends

2. 5-1Developement of the Periodic Table State the periodic law Discuss contributions that Dobereiner, Newlands, Mendeleev, and Mosely made to the periodic table

3. What do you organize? • The development of the periodic table was one of the biggest achievements of chemistry • It brought order to thousands of ideas and what seemed like unrelated facts • It helped chemists predict the existence of elements that hadn’t been discovered yet

4. Forerunners of the Periodic Table • 1790’s - only knew of 23 elements • 1800’s - Introduction of electricity helped break compounds down into elements scientists didn’t know existed. • mid-1800’s Industrial Revolution – new chemistry related industries • 1870 - 70 known elements

5. Forerunners of the Periodic Table • J.W. Dobereiner (1780-1849) • In early 1800’s classified elements into groups of three • Could see a pattern of similar traits • Called the sets, triads • Example: lithium, sodium, potassium calcium, strontium, barium chlorine, bromine, iodine • Placed them in this order b/c the middle element has a mass equal to the average masses of the other 2 • atomic mass of Br = 79.9 • avg atomic mass of Cl and I = (35.5+126.9)/2 = 81.2

6. Forerunners of the Periodic Table • J.A.R. Newlands (1837-1898) • In 1865, first to see a pattern • Realized the elements’ properties were repeating after every 8th element • Called the pattern the law of octaves after the music scale • Pointed out the was a repetition or “periodic” trend to the properties

7. Forerunners of the Periodic Table • Dmitri Mendeleev (1834-1907) and Lothar Meyer (1830-1895) • In 1869, published nearly identical classification methods • Mendeleev’s is more well known • Classified elements by their atomic masses

8. The Periodic Law • Henry Moseley (1887-1915) • Student working in Rutherford’s lab • In 1913, reorganized the periodic table according to atomic numbers

9. The Periodic Law • States: • When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern

10. Section Review • Restate the Periodic Law in your own words • How were Dobereiner and Newlands’ ideas helpful in creating the periodic table? • What did Moseley’s work contribute to the development of the periodic table? • Which property did Mendeleev arrange his periodic table?

11. 5-2 Reading the Periodic Table Explain why elements in a group have similar properties Identify the four blocks of the periodic table

12. Organizing the Squares • Groups: columns • Periods: rows

13. Labeling and Naming Groups • Alkali metals: group 1 • Alkaline earth metals: group 2 • Halogens: group 7 • Noble gases: group 8 • Transition metals: groups in the middle

14. Metals, Nonmetals, and Metalloids • Metals: most of the elements on the table • Great conductors of electricity • Malleable (able to hammer into thin sheets) • Ductile (able to be made into wires) • Very shiny

15. Metals, Nonmetals, and Metalloids • Nonmetals • Upper right hand corner of table • Usually gases Neon Bromine

16. Metals, Nonmetals, and Metalloids • Metalloids • Have a combo of metal and nonmetal properties • Elements that touch the stair step line • Exceptions: boron and aluminum

17. Practice Problems • For the following elements find: • the element symbol • atomic number • classify it as a metal, nonmetal, or metalloid • name the group it is in if it has one • Iodine • Magnesium • Gold • Lithium • Argon • Chlorine • Barium • Cesium • Strontium • Silicon • Xenon

18. Label your periodic table activity

19. Electron Configuration and the Periodic Table • Take a look: • Period 1 hydrogen 1s1 • Period 2 lithium 1s22s1 • Period 3 sodium 1s22s22p63s1 • Period 4 potassium 1s22s22p63s23p64s1 • What do they have in common? • A single electron in their outside orbital

20. Electron Configuration and the Periodic Table • Valence electrons: electrons in the highest principle energy level • How many valence electrons does Be have? • 2 • How many valence electrons does Mg have? • 2 • How many valence electrons does Ca have? • 2

21. Electron Configuration and the Periodic Table • Atoms in the same group have similar chemproperties because they have the same # of valence electrons • Elements in group 1A have one valence e- • Elements in group 2A have two valence e- • Elements in group 8A have eight valence e-

22. Electron Configuration and the Periodic Table • The period number and the principle energy level number are equal to each other • Li: period 2 and its e- config • 1s22s1 • Ga: period 4 and e- config. • 1s22s22p63s23p64s23d104p1 • What is the e- config. for the group 1A element in the 6th period? • 1s22s22p63s23p64s23d104p65s24d105p66s1

23. The s-, p-, d-, and f-block Elements • s-block elements • Groups 1A and 2A plus hydrogen and helium • Group 1A: have one valence electron and the electron config. ends in s1 • Group 2A: have two valence electrons and the electron config. ends in s2 • Because only 2 e- fit in the s orbitals, there are only two “s” groups

24. S block

25. The s-, p-, d-, and f-block Elements • p-block elements • Filled after the s sublevel • Groups 3A – 8A • Group 8A elements are incredibly stable b/c both the s and p orbitals are filled

26. p-blocks s-blocks

27. The s-, p-, d-, and f-block Elements • d-block elements • Contains transition elements • d orbitals can fit up to 10 electrons so there are a total of 10 groups • Group B elements

28. p-blocks s-blocks d-blocks

29. The s-, p-, d-, and f-block Elements • f-block elements • Inner transition metals • f orbitals can hold up to 14 electrons so there are 14 groups/columns

30. p-blocks s-blocks d-blocks f-blocks

31. 5-3 Periodic Trends Define the term periodic trend Identify 4 important periodic trends and explain how each reflects the electron configurations of the elements

32. Atomic Radius • Half the distance b/w the nucleus of one atom and the nucleus of the closest atom next to it d 2

33. Atomic Radius • Trends in periods • Decreases as you go right • Trends in groups • Increases as you go down

35. Ionic Size • Atoms can gain and lose electrons • When they do, they form ions • When they lose e-, they grow smaller • When they gain e-, they grow larger • Trends within periods • Decrease as you move right until Nitrogen • Trends within groups • Increase as you move down

37. Ionization Energy • Energy needed to remove an electron from an element/atom • The more electrons you remove, the more energy is needed • Trends within periods • Increase as you move right • Trends within groups • Decrease as you move down

39. Practice Problems • Boron, carbon, and aluminum occur near each other in the periodic table, which is the largest? Which has the highest ionization nrg? • Al is largest and C has highest ionization nrg • Which of the following atoms is smallest: lithium, beryllium, or magnesium? Which has the highest ionization nrg? • Be is smallest and has highest ionization nrg • Which of the following is the largest: a sodium atom, a sodium atom with a +1, or a potassium atom? • K atom

40. Octet rule • Atoms tend to gain, lose, or share electrons in order to get a full set of eight electrons • Atoms will do anything to get these eight

41. Electronegativity • The relative ability of atoms to attract electrons to themselves • Trends within periods • Increases as you move right • Trends within groups • Decreases as you move down