The Periodic Table

1. The Periodic Table • The Periodic Table is used to organize the 114 elements in a meaningful way. • As a consequence of this organization, there are periodic properties associated with the periodic table.

2. Reading the Periodic Table - The Basics Families or groups – vertical columns - have similar properties - contain the same outer electron configuration - show similar chemical behavior because it is the outer electrons involved in chemical reactions - 18 groups - Various ways of labeling and naming Roman numerals + letter (European) Arabic numerals + letter (American) Arabic numerals 1-18 (IUPAC) Periods= Horizontal rows #’d 1-7 Each period contains more and more elements

3. The Periodic Table

5. The periodic table shows all of the known elements in order of increasing atomic number.

6. The periodic table is organized to group elements with similar properties in vertical columns. • Some of the groups in the periodic table are given special names. • These names indicate the similarities between group members: • Group 1: Alkali metals. • Group 2: Alkaline earth metals. • Group 17: Halogens. • Group 18: Noble gases.

7. Patterns of Elements…. • Most elements are metals and occur on the left side. • The nonmetals appear on the right side. • Metalloids are elements that have some metallic and some nonmetallic properties.

8. Other Groups/Areas on the Periodic Table Representative or Main Group Elements = Groups 1,2 and 13-18 Transition metals = Groups 3-12 Inner transition elements (metals) = Element #’s 57-71 (Lantanides) and Element #’s 89-103 (Actinides)

9. Representative or Main Group Elements = Groups 1,2 and 13-18 Transition metals = Groups 3-12

10. Inner transition elements (metals) = Element #’s 57-71 (Lanthanides) and Element #’s 89-103 (Actinides)

11. The Periodic Table with the Inner Transition Elements in Place

12. Patterns of Elements…. • Most elements are metals and occur on the left side. • The nonmetals appear on the right side. • Metalloids are elements that have some metallic and some nonmetallic properties.

13. Comparison of Metals and Nonmetals Metals Nonmetals - Found on the right side of the periodic table Nonmetals tend to gain electrons! Nonmetallic Properties: Poor reflectors of light, Hard or brittle, some are gases or soft solids Not malleable or ductile Do not conduct electricity, Poor conductor of heat - Found on the left side of the periodic table. (Most elements are metals.) Metals tend to lose electrons! Metallic Properties: • Luster: most metals have a silvery white “metallic” color because they reflect light of all wavelengths. • Ductile, (capable of being drawn out into a wire) • Malleable (can be hammered into thin sheets) • Most semisolids @ room Tº • High electrical conductivity & thermal conductivity

14. Metalloids or Semimetals • Found along jagged line on table • Metalloids lose or gain or SHARE electrons depending on "who they're with!“ • Mixture of both types of properties, or intermediate type Examples: B, Si, Ge, As, Sb, Te, At (the only metal on the solid "semimetal" line is Al.) Natural States of the Elements Most elements are very reactive. Elements are not generally found in uncombined form. Exceptions are: Noble metals – gold, platinum and silver Noble gases – Group 8

15. Diatomic Nonmetals • Diatomic Molecules Nitrogen gas contains N2 molecules. Oxygen gas contains O2 molecules.

16. Information in an Element’s “Box” on the Periodic Table • Atomic Number = the number of protons • Atomic Mass = Weighted average of all of the isotopes of the element • Mass number (for a particular isotope) = # protons + # o f neutrons. • http://www.crystalgraphics.com/powerpictures/images.photos.asp?page=2&testing=0&qs=yes&ss=uranium&ipp=48&c=page&newflag=all

17. Introduction to the Modern Concept of Atomic Structure Comparing the Parts of an Atom

18. Comparing Subatomic Particles

19. Atomic Mass and Formula Mass • To calculate the mass of a sample of atoms • Each element exists as a mixture of isotopes • Use a “weighted average” for the atomic mass • Number on the bottom of each square in the periodic table is the average weightof all the isotopes of an element • (in amu)

20. Atomic Mass • Atomic masses are determined on a relative scale • The standard scale references the carbon-12 isotope = 12.000 amu • All other atomic masses are determined relative to carbon-12

21. Atomic Mass Units

22. Atomic Mass Na 22.99 • Listed on the periodic table • Gives the mass of “average” atom of each element compared to 12C • Average atom based on all the isotopes and their abundance % • Atomic mass is not a whole number

23. Isotopes • Isotopes are atoms with the same number of protons but different numbers of neutrons.

24. Isotopes • A particular isotope is represented by the symbol. Only use this symbol when you know the number of neutrons exactly.

25. Calculating Atomic Mass • Percent(%) abundance of isotopes • Mass of each isotope of that element • Weighted average = mass isotope1(%) + mass isotope2(%) + … 100 100

26. Calculating #s’s of Subatomic Particles; Protons, Neutrons and Electrons • The atomic number = the number of protons. • If the atom is neutral, the number of electrons equals the number of protons • Mass number of an isotope = Protons + Neutrons therefore Mass # - Atomic number = # neutrons.

27. More Atomic Symbols 16 31 65 O P Zn 8 15 30 8 p+ 15 p+ 30 p+ 8 n 16 n 35 n 8 e- 15e- 30 e-

28. Ions – Charged Particles • Atoms can form ions by gaining or losing electrons. Metals tend to lose one or more electrons to form positive ions called cations.

29. Ions – Charged Particles • Nonmetals tend to gain one or more electrons to form negative ions called anions.

30. Isotopes Cobalt - 59 Helium - 4 https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcTHz7dqYS1wSMjONCGFFjQ6adqoAI9YrcUgqzeQVoazzI2sWp8h-wqsONE • http://www.expertsmind.com/CMSImages/883_calculate-nautron-number.png

31. Ions Ion Charges and the Periodic Table • The ion that a particular atom will form can be predicted from the periodic table. • Elements in Group 1 and 2 form 1+ and 2+ ions, respectively • Group 7 atoms form anions with 1- charges • Group 6 atoms form anions with 2- charges • when compared to the neutral atoms • Cations have fewer electrons than protons • Anions have extra electrons (more) than protons

32. Common Monatomic Ions EOS