Atomic Trends Periodic Table

1. Atomic TrendsPeriodic Table

2. Starting Question What Periodic Trends exist on the periodic table going left to right per row on the table?

3. Reason for lesson • Today we are going add to our knowledge of the periodic table and introduce the important ideas of the periodic law,electronegativity, ionization energy, electron affinity and shielding effects. • Order discoverers.

4. Uun 110 Uuu 111 Uub 112 Uuq 113 Uuh 116 Uuo 118 The Periodic Table Noble gases Alkaline earth metals Halogens 1 18 H 1 He 2 2 13 14 15 16 17 Li 3 Be 4 B 5 C 6 N 7 O 8 F 9 Ne 10 3 4 5 6 7 8 9 10 11 12 Na 11 Mg 12 Al 13 Si 14 P 15 S 16 Cl 17 Ar 18 Transition metals K 19 Ca 20 Sc 21 Ti 22 V 23 Cr 24 Mn 25 Fe 26 Co 27 Ni 28 Cu 29 Zn 30 Ga 31 Ge 32 As 33 Se 34 Br 35 Kr 36 Alkali metals Rb 37 Sr 38 Y 39 Zr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48 In 49 Sn 50 Sb 51 Te 52 I 53 Xe 54 Cs 55 Ba 56 * Hf 72 Ta 73 W 74 Re 75 Os 76 Ir 77 Pt 78 Au 79 Hg 80 Tl 81 Pb 82 Bi 83 Po 84 At 85 Rn 86 Fr 87 Ra 88 Y Rf 104 Db 105 Sg 106 Bh 107 Hs 108 Mt 109 * Lanthanides La 57 Ce 58 Pr 59 Nd 60 Pm 61 Sm 62 Eu 63 Gd 64 Tb 65 Dy 66 Ho 67 Er 68 Tm 69 Yb 70 Lu 71 Ac 89 Th 90 Pa 91 U 92 Np 93 Pu 94 Am 95 Cm 96 Bk 97 Cf 98 Es 99 Fm 100 Md 101 No 102 Lr 103 Y Actinides

5. Orbitals Being Filled 1 8 Groups 2 1s 1 3 4 5 6 7 1s 2s 2 2p 3s 3p 3 4p 3d Periods 4s 4 4d 5p 5s 5 La 5d 6p 6 6s Ac 6d 7 7s 4f Lanthanide series 5f Actinide series Zumdahl, Zumdahl, DeCoste, World of Chemistry2002, page 345

6. Electron Filling in Periodic Table s s p 1 2 d 3 4 5 * 6 W 7 f * W

7. Electron Filling in Periodic Table metallic character increases nonmetallic character increases metallic character increases nonmetallic character increases

8. Atomic Trends • The number of protons and electrons affects the properties of an atom. • The periodic table is organized according to groups (up and down) and periods (right to left).

9. Atomic Trends • There are a number of atomic characteristics that either increase or decrease along the periodic table:

10. Atomic Radius • Atomic Radius: the size of the atom. If you compare two atoms that are directly above and below each other on the table, the one underneath will be larger because it is at a higher primary energy level.(more electron orbits)

11. Example of Atomic Radius

12. Atomic Radius (continued) • However, if you compare two atoms that are side-by-side on the table, the one on the left will be larger because when you add more electrons and protons, the electric force that pulls them together will increase, making the radius smaller.

13. Atomic Radius (continued) • Electrons in the same orbit relative to other electrons experience MORE PULL by the protons as the atomic number increases – this pulls the electrons slightly closer (the PULL is often referred to as CORE CHARGE) • Core Charge = No. of Protons – No. of nonvalence electrons • Sodium has 11 protons • CC = +11 – 10(non valence electrons) = +1

14. Ionisation Energy • Ionization Energy— • the amount of energy that is required to remove an electron. • If an atom will easily lose an electron (like the Alkali Metals), the ionization energy will be low. • If it will not lose electrons easily (noble gases, Halogens), the ionization energy will be high..

15. Ionization Energy (cont.) • Ionization energy increases going left to right on the table, and decreases going down. • Larger atoms lose electrons more easily because the electric force is less because the distance from the nucleus is greater. (shielding effect)

16. Why electrons are held more strongly up and to the right in a periodic table. • Across a period, the additional positive charge holds electrons more strongly. • Down a family, the atom becomes much larger, so the electrons experience less influence from the nucleus.

17. Shielding effect • The idea that the inner electron shells insulate the valence electrons from the positive charge of the nucleus so the outer electrons are not held as strongly as they would be without the presence of those inner electron shells.

18. Electron affinity • Affinity means attraction or liking. You may have an affinity for ice cream. • Different atoms will have a stronger or weaker affinity for electrons. • You may prefer Neapolitan to Rocky Road. • Electron Affinity: the energy change that accompanies the addition of an electron to an atom in the gas phase.

19. Electron Affinity • Electron Affinity- • the ability of an atom to gain an electron. This is closely related to ionization energy, and increases going left to right, and decreases going down.

20. Electron Affinity • As the core charge increases left to right on the table (the pull increases) electron more easily accepted • As the electron shell orbits are enlarged, less pull (shielding effect) so lower electron affinity

21. Electronegativity • Electronegativity- • Ability of an atom to attract electrons when in a molecule.Generally, the smaller the atom the higher the electronegativity. Noble gasses have zero electronegativity.

22. Electronegativity (cont.) • This increases going left to right, and decreases going down (with the exception of noble gases, which don’t make molecules with other atoms).

23. Stability and Graphing • The elements undergo physical and chemical transformations to become more stable. One way to achieve stability is to have a filled s, p, d or f suborbital. In addition, a half filled orbital is more stable than a less than half or more than half filled sublevel.

24. Discussion Questions • What elements valence electrons are more shielded from its nucleus, those of Potassium or those of Francium?

25. Questions to Ponder • When an atom loses an electron to become an ion, what happens to the electric charge? To its size? When an atom gains an electron to become an ion, what happens to its charge? To its size? • Ion: a molecule or atom with a positive or negative charge. Cation: positive, Anion:negative. • Arrange the following atoms to show a trend of increasing atomic radius: potassium, carbon, rubidium, iodine, fluorine and lithium.

26. Questions to Ponder • Arrange these elements in terms of increasing electronegativity values: fluorine, nitrogen, calcium, germanium, oxygen and bromine.

27. Summary of Periodic Trends • That hydrogen is considered to be a family by itself. • Periodic trends in ionization energy, electronegativity, radius, electron affinity, reactivity, electrical conductivity and hardness. • Trends in groups such as radius and shielding. • The relationship between electron configuration and electrical conductivity. • The relationship between atomic number and atomic radius within a group. • That elements are more similar within a group that within a period. • The number of protons and electrons affects the properties of an atom.

28. Summary of Periodic Trends • The periodic table is organized according to groups (up and down) and periods (right to left). • If you compare two atoms that are directly above and below each other on the table, the one underneath will be larger because it is at a higher primary energy level. • compare two atoms that are side-by-side on the table, the one on the left will be larger because when you add more electrons and protons, the electric force that pulls them together will increase, making the radius smaller.

29. Summary of Periodic Trends • Ionization energy increases going left to right on the table, and decreases going down. • Electron Affinity--the ability of an atom to gain an electron. This is closely related to ionization energy, and increases going left to right, and decreases going down. • Electronegativity--Ability of an atom to attract electrons when in a molecule. • Across a period, the additional positive charge holds electrons more strongly. • Down a family, the atom becomes much larger, so the electrons experience less influence from the nucleus.

30. Shielding effect: The idea that the inner electron shells insulate the valence electrons from the positive charge of the nucleus so the outer electrons are not held as strongly as they would be without the presence of those inner electron shells. • The elements undergo physical and chemical transformations to become more stable. One way to achieve stability is to have a filled s, p, d or f suborbital. In addition, a half filled orbital is more stable than a less than half or more than half filled sublevel.