The Periodic Table and Periodic Law Chapter 6 The Periodic Table and Periodic Law

Chapter 6 Terms Group Period Ion Nonmetal Representative element Transition element Metal Alkali metal Alkaline earth metal Nonmetal Halogen Noble gas Metalloid Atomic radius Ionization energy Electronegativity Draw a periodic table. Label you PT using each term above (not ion). Draw arrows to define atomic radius, ionization energy, and electronegativity from inc to dec or dec to inc.

Development of the Modern Periodic Table Chapter 6.1 Development of the Modern Periodic Table

Behavior of Main Group Elements Elements in the same group (vertical column) of the periodic table have the same number of valence electrons, and because of this, they have similar properties. But elements in a period (horizontal row) have properties different from one another.

Behavior of Main Group Elements This is because the number of valence electrons increases from one to eight as you move from left to right. As a result, the character of the elements changes.

Behavior of Main Group Elements Each period begins with two or more metallic elements, which are followed by one or two metalloids. The metalloids are followed by nonmetallic elements, and every period ends with a noble gas.

Trends in Metallic Properties Periods

Elements Representative elements are the groups designated with an A (1A through 8A) Transition elements are the groups designated with a B (1B through 8B)

Classifying Elements Metals Nonmetals Metalloids Three main classes of elements Metals Nonmetals Metalloids

Classifying Elements: Metals Shiny solid at room temperature (r.t.) good conductors of heat and electricity. malleable and ductile

Classifying Elements: Metals Alkali Metals: Group 1A elements Alkaline Earth Metals: Group 2A elements Both are chemically reactive, with alkali metals being more reactive than alkaline earth metals.

Classifying Elements: Metals Transition Metals: Group B elements, are divided into 2 categories Inner Transition Metals: Two sets of series, lanthanide and actinide (more in Chap. 7). They are located along the bottom of the PT. Transition Metals: Make up the rest of Group B elements

Classifying Elements: Metals Nonmetals: Occupy the upper right side of the PT (yellow boxes). gases or brittle, dull looking solids. Poor conductors of heat and electricity. Bromine is the only nonmetal that is liquid at r.t. Halogens: Group 7A elements. Highly reactive. Noble Gases: Group 8A elements. Highly unreactive.

Classifying Elements: Metals Metalloids: The green boxes that are the zigzag line separating the metals and nonmetals. They have physical and chemical properties of both metals and nonmetals.

Chapter 6.3 Periodic Trends

Atomic Radii Atom size increases in a group of elements as you go down because valence electrons are found in energy levels farther from the nucleus. Atom size decreases in a period because the outer electrons are attracted more strongly toward the nucleus. Figure 6.11c Page 163

Atomic Radii = 1 Angstrom IA IIA IIIA IVA VA VIA VIIA Li Na K Rb Cs Cl P Si Al Br Se As Ge Ga I Te Sb Sn In Tl Pb Bi Mg Ca Sr Ba Be F O N C B 1.52 1.11 1.86 1.60 2.31 1.97 2.44 2.15 2.62 2.17 0.88 0.77 0.70 0.66 0.64 1.43 1.17 1.10 1.04 0.99 1.22 1.22 1.21 1.17 1.14 1.62 1.40 1.41 1.37 1.33 1.71 1.75 1.46 = 1 Angstrom 17

Ionic Radius Atoms can gain or lose one or more electrons to form ions. Because electrons are negatively charged this causes atoms to acquire a net charge An ION is an atom that has a positive or negative charge. How does the formation of an ion affect the size of an atom???

Ionic Radius: Trends in Periods As you move left to right across a period the size of positive ions gradually decreases. Once you get to 5A or 6A the size of the larger negatively charged atoms becomes smaller. Check out Figure 6.14 on Page 166 for a diagram.

Ionic Radius: Trends in Groups As you move down in a group the size increases. This is for both positive and negative ions Check out Figure 6.14 on Page 166 for a diagram.

Ionic Radii Atomic Radii = 1 Angstrom = 1 Angstrom 0.60 0.31 0.95 0.65 1.33 0.99 1.48 1.13 1.69 1.35 1.71 1.40 1.36 0.50 1.84 1.81 0.62 1.98 1.85 0.81 2.21 2.16 0.95 IA IIA IIIA IVA VA VIA VIIA = 1 Angstrom Li1+ Be2+ Na1+ Mg2+ Ba2+ Sr2+ Ca2+ K1+ Rb1+ Cs1+ Cl1- N3- O2- F1- S2- Se2- Br1- Te2- I1- Al3+ Ga3+ In3+ Tl3+ IA IIA IIIA IVA VA VIA VIIA Li Na K Rb Cs Cl S P Si Al Br Se As Ge Ga I Te Sb Sn In Tl Pb Bi Mg Ca Sr Ba Be F O N C B 1.52 1.11 1.86 1.60 2.31 1.97 2.44 2.15 2.62 2.17 0.88 0.77 0.70 0.66 0.64 1.43 1.17 1.10 1.04 0.99 1.22 1.22 1.21 1.17 1.14 1.62 1.40 1.41 1.37 1.33 1.71 1.75 1.46 = 1 Angstrom 21

Ionization Energy To form the positive ion you need ENERGY! The energy needed is to overcome the attraction between the positive energy in nucleus and the charge of the electron. This is the IONIZATION ENERGY I.E. can be thought of as an indication of how strongly an atom’s nucleus holds onto the valance electrons.

Ionization Energy A high I.E. means the atom has a strong hold on its valance electrons. A low I.E. means the atom loses its valance electrons easily. It is possible for atoms to lose of gain more than one electron. The amount of energy required to do this is called the second ionization energy. So the third is…

Ionization Energies Period H He Mg Li Be B C N O F Ne Na Mg Al Si P S Group 1 18 H 1312 He 2372 1 1 Mg 738 Symbol First Ionization Energy (kJ/mol) 2 13 14 15 16 17 Li 520 Be 900 B 801 C 1086 N 1402 O 1314 F 1681 Ne 2081 2 2 Na 496 Mg 738 Al 578 Si 787 P 1012 S 1000 Cl 1251 Ar 1521 3 3 3 4 5 6 7 8 9 10 11 12 Period K 419 Ca 590 Sc 633 Ti 659 V 651 Cr 653 Mn 717 Fe 762 Co 760 Ni 737 Cu 746 Zn 906 Ga 579 Ge 762 As 947 Se 941 Br 1140 Kr 1351 4 4 Rb 403 Sr 550 Y 600 Zr 640 Nb 652 Mo 684 Tc 702 Ru 710 Rh 720 Pd 804 Ag 731 Cd 868 In 558 Sn 709 Sb 834 Te 869 I 1008 Xe 1170 5 5 Cs 376 Ba 503 La 538 * Hf 659 Ta 761 W 770 Re 760 Os 839 Ir 878 Pt 868 Au 890 Hg 1007 Tl 589 Pb 716 Bi 703 Po 812 At -- Rn 1038 6 6 Fr -- Ra 509 Ac 490 y Rf -- Db -- Sg -- Bh -- Hs -- Mt -- Ds -- Uuu -- Uub -- Uut -- Uuq -- Uup -- Uuo -- 7 * Lanthanide series Ce 534 Pr 527 Nd 533 Pm 536 Sm 545 Eu 547 Gd 592 Tb 566 Dy 573 Ho 581 Er 589 Tm 597 Yb 603 Lu 523 y Actinide series Th 587 Pa 570 U 598 Np 600 Pu 585 Am 578 Cm 581 Bk 601 Cf 608 Es 619 Fm 627 Md 635 No 642 Lr -- 24

Electronegativity Electronegativity indicates the relative ability of its atom to attract electrons. As you move from left to right in a period the electronegativity increases. As you move down in a group the electronegativity decreases. The lower left side of the periodic table has the lowest and the upper right has the highest!!

Electronegativities Period H B P As Se Ru Rh Pd Te Os Ir Pt Au Po At 2.1 B 2.0 P As Se 2.4 Ru 2.2 Rh Pd Te Os Ir Pt Au Po At 2.0 - 2.4 1 1 2A 3A 4A 5A 6A 7A Actinides: 1.3 - 1.5 Li 1.0 Ca Sc 1.3 Sr Y 1.2 Zr 1.4 Hf Mg La 1.1 Ac 1.0 - 1.4 Lanthanides: 1.1 - 1.3 * y Be 1.5 Al Si 1.8 Ti V 1.6 Cr Mn Fe Co Ni Cu 1.9 Zn 1.7 Ga Ge Nb Mo Tc Ag Cd In Sn Sb Ta W Re Hg Tl Pb Bi 1.5 - 1.9 C 2.5 S Br 2.8 I 2.5 - 2.9 N 3.0 O 3.5 F 4.0 Cl 3.0 - 4.0 2 2 Na 0.9 K 0.8 Rb Cs 0.7 Ba Fr Ra Below 1.0 3 3 3B 4B 5B 6B 7B 8B 1B 2B Period 4 4 5 5 6 6 7 26

Summary of Periodic Trends Atomic radius decreases Ionization energy increases Electronegativity increases 1A 2A 3A 4A 5A 6A 7A Ionization energy decreases Electronegativity decreases Atomic radius increases Ionic size increases Ionic size (cations) Ionic size (anions) decreases decreases 27