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Periodic Trends in Chemical Properties Chapter 3 – Green/Damji Chapter 8 - Chang Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction.

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Presentation on theme: "Periodic Trends in Chemical Properties Chapter 3 – Green/Damji Chapter 8 - Chang Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction."— Presentation transcript:

1 Periodic Trends in Chemical Properties Chapter 3 – Green/Damji Chapter 8 - Chang Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Group 1 Elements (ns 1, n 2) M M +1 + 1e - 2M (s) + 2H 2 O (l) 2MOH (aq) + H 2(g) 8.6 (Alkali) Metals react with water to form hydroxides – which are bases. (Alkali) Metals are electron donors, they form cations Write the corresponding equation for sodium:

3 Group 1 Elements Increasing reactivity 8.6 2M (s) + 2H 2 O (l) 2MOH (aq) + H 2(g) 2 Li (s) + 2 H 2 O (l) 2__________ (aq) + H 2(g) 2 Na (s) + 2 H 2 O (l) 2___________ (aq) + H 2(g) 2 K (s) + 2 H 2 O (l) 2 KOH (aq) + __________ slow and steady vigorous violent

4 Group 1 Elements (ns 1, n 2) 4M (s) + O 2(g) 2M 2 O (s) 8.6 (Alkali Metals react with oxygen to form metal oxides 2 M (s) + X 2(g) 2 MX (s) (Alkali) Metals react with halogens to form metal halides (salts) Write the corresponding equation for sodium:

5 Group 2 Elements (ns 2, n 2) M M +2 + 2e - Be (s) + 2H 2 O (l) No Reaction Increasing reactivity 8.6 Mg (s) + 2H 2 O (g) Mg(OH) 2(aq) + H 2(g) M (s) + 2H 2 O (l) M(OH) 2(aq) + H 2(g) M = Mg, Ca, Sr, or Ba

6 Group 3 Elements (ns 2 np 1, n 2) 8.6 4Al (s) + 3O 2(g) 2Al 2 O 3(s) 2Al (s) + 6H + (aq) 2Al 3+ (aq) + 3H 2(g)

7 Group 4 Elements (ns 2 np 2, n 2) 8.6 Sn (s) + 2H + (aq) Sn 2+ (aq) + H 2 (g) Pb (s) + 2H + (aq) Pb 2+ (aq) + H 2 (g)

8 Group 5 Elements (ns 2 np 3, n 2) 8.6 N 2 O 5(s) + H 2 O (l) 2HNO 3(aq) P 4 O 10(s) + 6H 2 O (l) 4H 3 PO 4(aq)

9 Group 6 Elements (ns 2 np 4, n 2) 8.6 SO 3(g) + H 2 O (l) H 2 SO 4(aq)

10 Group 7 Elements (ns 2 np 5, n 2) X 2 + 2e - 2 X - 1 X 2(g) + H 2(g) 2HX (g) 8.6 Halogens are electron acceptors, form anions Halogens react with hydrogen to form hydrogen halides (which are acids ) Write the corresponding equation for chlorine: Write the corresponding equation for bromine:

11 Group 7 Elements (ns 2 np 5, n 2) 8.6 [Note: HCl is hydrochloric acid, a strong acid and HOCl (aq) is chloric acid, a weak acid ] X 2(g) + H 2 O (g) 2HX (aq) + HOX (aq) Halogens react with water to form acids ) Write the corresponding equation for chlorine:

12 Group 7 Elements (ns 2 np 5, n 2) Increasing reactivity 8.6 Metals react with halogens to form metallic halides… The level of reactivity depends on the trends of reactivity for both the metal and the halogen… Increasing reactivity

13 Reactivity of Metals with Halogens Ex: Which of the following pairs of chemicals will react most vigorously? Least vigorously? K and Br 2 Li and I 2 Na and I 2 Na and F 2 K and F 2 Li and Br 2 2 M (s) + X 2(g) 2 MX (s) Write the corresponding equations:

14 Reactivity of Halogens with Halides 2 M + X - (aq) + X 2(aq) 2 M + X - (aq) + X 2 (aq) Cl 2 (aq) + 2 Na + Br - (aq) 2 Na + Cl - (aq) + Br 2 (aq) Cl 2 (aq) + 2 Na + I - (aq) 2 Na + Cl - (aq) + I 2 (aq) Br 2 (aq) + 2 Na + I - (aq) 2 Na + Br - (aq) + I 2 (aq) F 2 (aq) + 2 Na + Br - (aq) 2 Na + F - (aq) + Br 2 (aq) F 2 (aq) + 2 Na + Cl - (aq) 2 Na + F - (aq) + Cl 2 (aq) F 2 (aq) + 2 Na + I - (aq) 2 Na + F - (aq) + I 2 (aq) Compare the reactions/reactivity with the position of the halogen / halide on the periodic table? What is the pattern?

15 Identifying halide ions The presence of halide ions can be detected by reacting the salt with lead or silver salts… and observing the resulting precipitates. They have characteristic colors. (You did this in lab ) Ag + (aq) + X (aq) AgX (s) Write the equations to test for chloride, bromide, and iodide:

16 Group 8A Elements (ns 2 np 6, n 2) 8.6 Completely filled ns and np subshells. Highest ionization energy of all elements. No tendency to accept extra electrons.

17 Properties of Oxides Across a Period (when added to water) basicacidic 8.6

18 Reactions of Oxides of Period 3 Oxides of metals react with water to form a base Na 2 O (s) + H 2 O (l) 2 Na + (aq) + 2 OH 1- (aq) (NOTE: Mg(OH) 2 is not very soluble.) Write the corresponding equation for magnesium oxide

19 Reactions of Oxides of Period 3 Oxides of metals can act as a base to neutralize an acid to form salt and water. MgO (s) + 2 HCl (aq) Mg 2+ (aq) + 2 Cl 1- (aq) + H 2 O (l) Write the corresponding equation for sodium oxide:

20 Reactions of Oxides of Period 3 Oxides of non metals react with water to form acids CO 2 (g) + H 2 O (l) H + (aq) + 2 HCO 3 1- (aq) SiO 2 (s) + H 2 O (l) not much of a reaction, however silicon dioxide will react as an acid to neutralize a base… SiO 2 (s) + 2 OH 1- (aq) SiO 3 2- (s) + H 2 O (l) P 4 O 10 (s) + 6 H 2 O (l) 4 H + (aq) + 4 H 2 PO 4 1- (aq) SO 3 (s) + H 2 O (l) H + (aq) + HSO 4 1- (aq)

21 Properties of Chlorides Across a Period (when added to water) neutralacidic 8.6 NaClMgCl 2 AlCl 3 (Al 2 Cl 6 (g) ) SiCl 4 PCl 3 PCl 5 SCl 2 Cl 2 Type of bondingionic giant covalent molecular covalent Structure crystalline solid (extensive 3D structure) solidliquidgas Properties high melting points sublimes at 178°C to give vapor low melting and boiling points conduct electricity in molten and (aq) states molten chlorides do NOT conduct electricity (no charged particles) aqueous chlorides DO conduct electricity Acid-Base Nature dissolve when added to water (neutral soln) react with water to form acidic soln

22 Reactions of Chlorides of Period 3 NaCl (s) + H 2 O (l) Na + (aq) + Cl - (aq) + H 2 O (l) (No reaction, just dissolving) (No reaction, just dissolving) Write the corresponding equation for magnesium chloride

23 Reactions of Chlorides of Period 3 AlCl 3 (s) + 3 H 2 O (l) Al(OH) 3 (s) + 3 H + (aq) + 3 Cl - (aq) SiCl 4 (l) + 2 H 2 O (l) SiO 2 (s) + 4 H + (aq) + 4 Cl - (aq) PCl 3 (l) + 3 H 2 O (l) P(OH) 3 (aq) + 3 H + (aq) + 3 Cl - (aq) [Note: P(OH) 3 (aq) is also known as phosphoric(III) acid H 3 PO 3, a weak acid ] PCl 5 (s) + 4 H 2 O (l) H 3 PO 4 (aq) + 5 H + (aq) + 5 Cl - (aq) [Note: H 3 PO 4 (aq) is known as phosphoric(V) acid, which is a strong acid ] Cl 2 (s) + H 2 O (l) H + (aq) + Cl - (aq) + HOCl (aq) [Note: HOCl (aq) is known as chloric acid and is a weak acid ] What patterns do you notice?

24 Ready for Homework? Exercise 3.3 p 80 # 1-10 due: __________ Exercise 13.1 p 84 # 1-5 due: __________ Suggestion – Work through the problems using the text and notes to answer the questions. Check your answers with the key. THEN, try to answer the problems again… without your notes.


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