The Periodic Table & Periodic Law. Chapter 6 Chemistry X

Transcription

1 The Periodic Table & Periodic Law Chapter 6 Chemistry X

2 History of the Periodic Table John Newlands Law of octaves Lothar Meyer Dmitri Mendeleev organized according to he saw repeating (periodic) trends Predicted the existence of Ga,, Sc, Ge LATER - Newly discovered elements did fit Mendeleev s s trends Henry Mosely organized according to

3 Periodic Law As atomic # increases, there is a periodic repetition of chemical and physical properties Groups families columns Periods series rows

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6 Periodic Table Label Metals/nonmetal/metalloids Label important group names Octet Rule: Write the Lewis Dot Structure for each element in the 3 rd period. Write the Lewis Dot Structure for the ion formed by each element in the 3 rd period.

7 Periodic Table 1) Draw the Electron Dot Structures (Lewis Dot Structures) for each of the following 2) What group # is this element from? 3) Indicate the number of valence electrons in each group. 4) Indicate the likely charge(s) for atoms in that group. He Na Mg Al Si P S Cl Ar group # # valence e- charge:

8 Periodic Table Make a line showing where the metalloids are located. Write the charges for ions formed by each group. Metals form (+) ions Nonmetals form (-)( ) ions

9 Alkali Metals Highly reactive React violently with water to produce H 2 gas very soft Francium is the most reactive

10 Alkaline Earth Metals Fairly reactive (not as much as group 1) React somewhat with water

11 Halogens highly reactive exist as diatomic molecules Fluorine is the most reactive

12 Noble Gases very unreactive inert Very stable He, Ne, Ar have never reacted

13 Transition Metals have 2 valence electrons can have multiple ion charges many compounds formed by these metals are colored

14 Inner Transition Metals or Rare Earth Elements Lanthanides & Actinides low abundance in nature actinides are synthetic & radioactive

15 What about Hydrogen? Acts like an alkali metal. By losing an electron to be like a noble gas Acts like a halogen by gaining an electron to be like a noble gas

16 Element Classification Metals Metalloids Nonmetals Conductor 1) 1) Semiconductors 1) Heat & electricity 2) malleable (exhibit 2) 3) ductile metallic/ nonmetallic 3) 4) lustrous properties) 4) 5) Most react w/acid Non-conductor brittle dull Solid/liquid/gas 6) Most react w/cucl 2

17 Metals Element Classification of elements Form ions room temp. except room temp. form ions Metalloids metalloids

18 Element Classification s-block metals are softer and not as dense as the p-block and d-block metals d-block are harder and denser than p-block and s-block melting/boiling points for metals as you go down columns, thus intermolecular forces as you go down columns. melting/boiling points for nonmetals as you go down columns, thus intermolecular forces as you go down columns. Metal reactivity increases columns and to the. Nonmetal reactivity increases columns and to the.

19 Periodic Trends Shielding/Z eff shielding effect the outer electrons can be shielded from the nuclear charge by the inner/core e-e Z eff Z effective the effective charge of the nucleus Z eff =

20 Periodic Trends Atomic Radii Atomic Radii one-half the distance between the nuclei of two identical atoms bonded together down columns across rows

21 Periodic Trends Ionization Energy Ionization Energy the energy require to remove an e-e Ion an atom that has a positive or negative charge Cation Anion - 1st IE the energy required to remove the first mole of e-e 2nd IE the energy required to remove

22 Periodic Trends Ionization Energy Element IE 1 IE 2 IE 3 IE 4 Li 124 1,748 2, Be ,532 5,004 B ,964

23 Periodic Trends Successive Ionization Energies It gets to remove successive electrons. There is a big jump in the amount of energy needed when

24 Periodic Trends Ionization Energy The following are Ionization energies for Na, Mg, and Al. Identify the set of IE s s that belong to each element. Element IE 1 IE 2 IE 3 IE 4 A 118 1,091 1, B ,767 C ,839 2,526 KEY: # electrons lost easily can tell us 1) 2)

25 Periodic Trends Successive Ionization Energies IE generally across periods IE generally down columns

26 Periodic Trends Ionization Energy Trend Diagram

27 Octet Rule Periodic Trends Ionization Energy

28 Periodic Trends Electron Affinity Electron Affinity the energy change that occurs when an e-e is acquired by a neutral atom

29 Periodic Trends Electron Affinity The trend is the same as for I.E., but not as regular Note: It s s always to add a second electron

30 Periodic Trends Electronegativity Electronegativity a measure of the ability of an atom to attract e-e Tends to across periods Tends to down columns the most electronegative atom is.

31 Ionic Radii Periodic Trends Ionic Radii Cation Anion See next slide for ionic radii diagram.

32 Ionic Radii - diagram

33 isoelectric - Periodic Trends Ionic Radii

34 Trend Summary Boxes 1

35 Trend Summary Boxes 2

36 Click on Chemistry X JEOPARDY!!! (in ch box)

37 Trend Summary Trend Summary Fill-in in table Z eff Shielding effect Ionization energy Electronegativity e- affinity Atomic radii Zeff Shielding effect Ionization energy Electronegativity e- affinity Atomic radii

38 Trend Summary