The Periodic Table: Tour of the Periodic Table – Key Terms

1. The Periodic Table: Tour of the Periodic Table – Key Terms • Main-group elements – ones in s-and p-blocks of the table that are called representative elements because they have a wide range of properties. • See Figure 5 on page 124.

2. Key Terms 2 • Main group elements have special sub groups like alkali metals (Group 1), alkaline-earth metals (Group 2), halogens (Group 17) & noble gases (Group 18). • See Fig. 6 pg 125 for alkali metals which react with water to make alkaline solutions (pH > 7.0).

3. Key Terms 3 • Alkali metals can be cut by a knife but lose the newly exposed shiny surface because the metal reacts with H2O & O in the air. • See Table 3 page 125 for their physical properties.

4. Key Terms 4 • These metals are very reactive because they only have 1 valence electron, and losing it results in a stable electron configuration. • Transition metal – one that bonds with electrons in its inner shell before its outer shell

5. Key Terms 5 • Ductile – squeezable into wire • Alloy – solid or liquid mixture of 2 or more metals • Lanthanide – member of the rare-earth series with an atomic # bet-ween 58 (cerium) & 71 (lutetium)

6. Key Terms 6 • Actinide – any element of the actinide series where its atomic number falls between 89 (actinium, Ac) through 103 (lawrencium, Lr)

7. Tour of the Periodic Table:Things To Do • Locate the different families of main-group elements on the periodic table. • Describe their characteristic properties and relate these to their electron configurations.

8. Things To Do 2 • Locate other metals on the periodic table. • Describe their characteristic properties and relate these to their electron configurations.

9. Tour of the Periodic Table – Main Group Elements • S- & p-block elements with regu-lar electron configurations (EC). • Same group = same # of valence electrons whose configurations are ns1 to ns2p6. • Here, n is the series or row #.

10. Main Group Elements 2 • Row # doubles as the energy level & principal quantum #. • For example, a Row 3 Group 2 element (Mg) would have an EC of 3s2. • Group 16 in this row (Sulfur) would have an EC of 3s23p4.

11. Main Group Elements 3 • Since these elements are in the s- & p-blocks, their valence electrons occupy s & p orbitals. • Group 2 alkaline-earth metals are slightly less reactive because they have 2 valence electrons.

12. Main Group Elements 4 • It takes more time and energy to lose 2 electrons than one. • Group 17 Halogens are very reactive because they need only 1 valence electron to have a full outermost energy level.

13. Main Group Elements 5 • Groups 1 & 17 are alike in needing to move only one valence electron. • However the 1st group loses but the 2nd one gains an electron.

14. Main Group Elements 6 • Halogens are the most reactive nonmetals & react with metals to form salts like NaCl. • Calcium is the best know alkaline-earth (Group 2) metal; it’s in bone, limestone, marble & teeth.

15. Main Group Elements 7 • Noble gases in group 18 are mostly unreactive not inert. • They have a full outermost energy levels but can be made to react under extreme circumstances.

16. Main Group Elements 8 • The strong stability and resultant low reactivity allow special uses like filling blimps. • H is in a solo class because it is the most common element. • H’s used to make ammonia, NH3, which is used to make fertilizer.

17. Most Elements Are Metals • Study Figure 11 on page 128. • Metals share many properties like being great heat and electricity conductors, ductile & malleable. • Transition metals are in the center of the periodic table, Groups 3-12.

18. Most Elements Are Metals 2 • Groups of transition metals or d-block elements do not have the same # of valence electrons. • HOWEVER, THE SUM OF THE OUTER d & s ELECTRONS = THE GROUP #. • They can lose 1 to 3 valence electrons, have lower reactivity than Groups 1-2 metals but keep other metal properties.

19. Most Elements Are Metals 3 • Lanthanides & actinides fill f-orbitals but are placed toward the bottom of the table in two rows to keep the table narrow. • Lanthanides = name of the 1st of these rows because in it elements have atomic #’s that follow lanthanum.

20. Most Elements Are Metals 4 • Actinides = name because elements in the row beneath lanthanides have atomic #’s that follow actinium. • Left to right in these rows, electrons get added to 4f-orbitals in the lanthanides but 5f ones in the actinides.

21. Most Elements Are Metals 5 • For actinides, the nuclear structure is more important than electron configuration. • This is because their nuclei are unstable, and as a result they spontaneously break apart & cause radioactivity. • Uranium is the best-known actinide.

22. Most Elements Are Metals 6 • Some other properties of metals include widely varying melting points with the highest (W, 4322˚C) and among the lowest ones (Hg, -39˚C). • They can be mixed to make alloys that eliminate the disadvantages of the solo metals.

23. Most Elements Are Metals 7 • For example, brass is Cu & Zn, which is harder than Cu and more resistant to corrosion. • Sterling silver is mostly Ag with a little Cu. • Steel is mostly Fe but has 0.2% - 1.5% carbon atoms & usually tiny amounts of other elements like Mn and Ni.

24. Most Elements Are Metals 8 • Consider finding an element in nature still in its pure elemental state. • What does this reveal about its reactivity?