Unit 4: The Periodic Table

Transcription

1 Unit 4 Periodic Table Notes (filled in).notebook Unit 4: The Periodic Table Review Book: Topic 2 Textbook: Ch. 5 & 14 What is an example of something that is "periodic"? school schedule, sunrise/sunset What does "periodic" mean? repeating I. History A. Dmitri Mendeleev (1800s) Russian chemist arranged elements by their properties Look at the Periodic Table with a neighbor. See if you can figure out how the elements are organized/arranged in the table. ex: Are the elements arranged alphabetically? (I. History) B. Henry Moseley (late 1800s) British physicist developed the modern Periodic Table Periodic Law: properties of the elements are periodic (repeating) functions of their atomic NUMBERS

2 II. The Table A. Periods (horizontal rows) # of energy levels B. Groups (vertical columns) elements have similar chemical properties (II. The Table) 1. Which element is in Period 4 and Group 2? Ca 2. Which element is in Period 3 and has 5 valence electrons? P 3. Which element is in Group 1 and has 5 energy levels? Rb 4. In which period is Cl located? 3 5. In which group is oxygen located? 16 Phys. prop. Metals Metalloids Nonmetals malleable ductile shiny excellent conductors (heat, electricity... MOBILE e 's) Chem. lose e 's prop. form + ions low E.N. low I.E. inbetween B, Si, Ge, As, Sb, Te brittle dull poor conductors (heat, electricity) gain e 's form ions high E.N. high I.E. A. Metals * positive nuclei surrounded by a "sea" of mobile e 's (moving charges allow for electrical conductivity) A. Metals... left side of staircase

3 1. Group 1 (alkali metals) have 1 valence e VERY active (UNSTABLE) form ions w/ a +1 charge found in compounds (bonded to other atoms more stable) ex: Na in water vs. NaCl in water Alkali Metals Video! v=qsz 3wScePM Group 2 Metals Video! v=b2zprg9iveo 2. Group 2 (alkaline earth metals) have 2 valence e 's less active form ions w/ a +2 charge 3. Transition metals: Groups 3 12 form colored solutions (aq) high melting points (hard metals) B. Metalloids: "staircase" C. Nonmetals 1. Group 17 (halogens) very active nonmetals tend to bond with Group 1 & 2 metals

4 Unit 4 Periodic Table Notes (filled in).notebook 2. Group 18 (noble gases) NOT reactive (very stable) have 8 valence e 's (octet rule) except He * MONATOMIC gases Why do you think that Group 1 and Group 17 elements are very reactive? D. Diatomic Elements Br2, I2, N2, Cl2, H2, O2, F2 "7H Club" exist as two atoms bonded together IV. State at STP B. Liquids Br2 Hg (mercury) IV. State at STP A. Gases Noble gases N2, Cl2, H2, O2, F 2 IV. State at STP C. Solids I2 everything else

5 IV. State at STP *To figure out: use Table S see where 273 K fits below m.p. = solid between m.p. and b.p. = liquid above b.p. = gas 273 A. Atomic radius: size of an atom and B. Metallic character: how much like a metal an element is s l g decrease across increase down C. Ionization energy: energy to REMOVE an e and D. Electronegativity: attraction for e in a bond w/ another atom scale of 0 to 4 (4 = highest) increase across decrease down *To figure out: use Table S pick a Period (row) or Group (column) and note the values of the elements ex: Going across Period 2, what is the trend in atomic radius? ex: Going down Group 1, what is the trend in ionization energy? Why do atoms get smaller as you go across a Period? more protons in the nucleus can hold e 's closer Why do atoms get smaller as you go up a Group? fewer electron shells

6 The noble gases do not have electronegativity values. Why not? E.N. is attraction for e 's in a bond with another atom. Noble gases are already stable and don't want to bond. Which are more chemically similar elements in the same Period or elements in the same Group? Explain. Elements in the same group are more chemically similar because they have the same # of valence e 's What is the relationship between electronegativity and ionization energy? Explain why this is so. direct relationship: the more an atom is attracted to e 's, the more energy it will take to remove an e from it