Read: 7.2 WS 7.1 (Guided Reading WS due Monday) Make flashcards for the following polyatomic ions:

Transcription

1 Colossians 1:16 17 Christ is the one through whom God created everything in heaven and earth. He made the things we can see and the things we can't see.... Everything has been created through him and for him. He existed before everything else began, and he holds all creation together. 1of 45

2 The density of silicon is 2.33 g/cm 3. What is the volume of a piece of silicon that has a mass of 62.9 g? Show your work. Write your answer in scientific notation. Remember that density can be used as a conversion factor. For Si: 2.33 g = 1 cm 3 2of 45

3 Read: 7.2 WS 7.1 (Guided Reading WS due Monday) Make flashcards for the following polyatomic ions: hydroxide, nitrate, acetate, sulfate, carbonate, phosphate, chlorate, ammonium; pg. 257 On one side write the name (hydroxide) on the other side write the chemical formula, including the charge (OH ). Begin studying them! You will NEED to know these! Really! I m not kidding! 3of 45

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5 7.1 Ions Pyrite (FeS 2 ), a common mineral that emits sparks when struck against steel, is often mistaken for gold hence its nickname, fool s gold. Pyrite is an example of a crystalline solid. In this chapter, you will learn about crystalline solids composed of ions that are bonded together. But first you need to understand how ions form from neutral atoms. 5of 45

6 2. Determine the number of valence electrons in an atom of a representative element. 3. Explain how the octet rule applies to atoms of metallic and nonmetallic elements. 4. Describe how cations form. 5. Describe how anions form. 6. Learn the names and charges of common ions. 6of 45

7 Valence electrons: The electrons in the highest occupied energy level (not sublevel) in an atom Determines the chemical properties (reactivity) of an element Can be determined by group number for groups 1A 8A Examples: Group 1A has 1 valence e, 7A has 7 valence e 7of 45

8 Review How many valence electrons do group 5A elements have? A. 3 B. 4 C. 5 D. 6 8of 45

9 Review: How many valence electrons does fluorine have? A. 4 B. 5 C. 6 D. 7 9of 45

10 Review: How many valence electrons do the noble gases have? A. 2 B. 4 C. 6 D of 45

11 Valence electrons and families Write electron configurations for H, Li and Na (group 1A) H: 1s 1 Li: 1s 2,2s 1 Na: 1s 2,2s 2,2p 6,3s 1 Their outermost electron shell has the same # of e s 11 of 45

12 7.1 Ions > Valence Electrons Applications of Group 4A Elements Carbon Silicon Germanium 12 of 45

13 Write electron configurations for F, and Cl (group 7A) F: 1s 2,2s 2,2p 5 Cl: 1s 2,2s 2,2p 6,3s 2,3p 5 13 of 45

14 Electron dot structures: Lewis structures valence electrons are represented by DOTS find the number of valence electrons write the chemical symbol with dots around the atom representing valence e s 14 of 45

15 7.1 Ions > Valence Electrons Electron dot structures are diagrams that show valence electrons as dots. 15 of 45

16 Write electron dot structures for N, O and F 16 of 45

17 Electron configurations for ions follow the octet rule developed by Gilbert Lewis: All elements gain or lose electrons so that they have the same electron configuration as their nearest noble gas neighbor. 17 of 45

18 The octet rule in ions: Metallic elements tend to lose valence e, leaving a complete octet in the next lower energy level Most non metallic elements tend to gain e or share e to achieve a complete octet 18 of 45

19 Formation of cations Loss of electron results in a positively charged cation Representative elements by group: 1A forms 1+ cations 2A forms 2+ cations 3A forms 3+ cations 19 of 45

20 7.1 Ions > Formation of Cations You can represent the electron loss, or ionization, of the sodium atom by drawing the complete electron configuration of the atom and of the ion formed. 20 of 45

21 7.1 Ions > Formation of Cations The electron configuration of the sodium ion is the same as that of a neon atom. 21 of 45

22 7.1 Ions > Formation of Cations Using electron dot structures, you can show the ionization more simply. 22 of 45

23 7.1 Ions > Formation of Cations The sodium atoms in a sodium-vapor lamp ionize to form sodium cations. 23 of 45

24 7.1 Ions > Formation of Cations A magnesium atom attains the electron configuration of neon by losing both valence electrons. The loss of valence electrons produces a magnesium cation with a charge of of 45

25 7.1 Ions > Formation of Cations Walnuts are a good dietary source of magnesium. Magnesium ions (Mg 2+ ) aid in digestive processes. 25 of 45

26 7.1 Ions > Formation of Cations Cations of Group 1A elements always have a charge of 1+. Cations of group 2A elements always have a charge of of 45

27 Electron configurations of ions will have a full octet in outermost energy level Write the electron configuration for Na and Na+ Na: 1s 2, 2s 2, 2p 6, 3s 1 Na + : 1s 2, 2s 2, 2p 6 27 of 45

28 Transition metal cations Charges may vary: the same element may form more than one cation: Fe (iron) forms 2+ and 3+ ions Don t always follow the octet rule Example: silver (Ag) always has a 1+ charge has a pseudo noble gas e configuration: 18 e outermost energy level (full s,p, & d sublevels) 28 of 45

29 7.1 Ions > Formation of Cations A copper atom can ionize to form a 1+ cation (Cu + ). By losing its lone 4s electron, copper attains a pseudo noble-gas electron configuration. 29 of 45

30 Formation of anions The gain of a valence electron by a neutral atom produces an anion Write the electron configuration for Cl and Cl Cl: 1s 2, 2s 2, 2p 6, 3s 2,3p 5 Cl : 1s 2, 2s 2, 2p 6,3s 2,3p 6 30 of 45

31 Formation of anions by group: Group 5A forms 3 anions Group 6A forms 2 anions Group 7A forms 1 anions Naming non metallic anions Names of non metallic anions end in ide: Examples: sulfide, oxide, fluoride.. The group 7A ions are also called halide ions 31 of 45

32 7.1 Ions > Formation of Anions The figure shows the symbols of anions formed by some elements in Groups 5A, 6A, and 7A. 32 of 45

33 7.1 Ions > Formation of Anions A gain of one electron gives chlorine an octet and converts a chlorine atom into a chloride ion. It has the same electron configuration as the noble gas argon. 33 of 45

34 7.1 Ions > Formation of Anions Both a chloride ion and the argon atom have an octet of electrons in their highest occupied energy levels. 34 of 45

35 7.1 Ions > Formation of Anions In this equation, each dot in the electron dot structure represents an electron in the valence shell in the electron configuration diagram. 35 of 45

36 7.1 Ions > Formation of Anions The negatively charged ions in seawater the anions are mostly chloride ions. 36 of 45

37 7.1 Ions > Formation of Anions The ions that are produced when atoms of chlorine and other halogens gain electrons are called halide ions. All halogen atoms have seven valence electrons. All halogen atoms need to gain only one electron to achieve the electron configuration of a noble gas. 37 of 45

38 7.1 Ions > Formation of Anions Oxygen is in Group 6A. 38 of 45

39 7.1 Ions > Formation of Anions 39 of 45

40 Review What is the charge of halide ions? A. 1+ B. 2+ C. 1 D of 45

41 7.1 Section Quiz. How many valence electrons are there in an atom of oxygen? A. 2 B. 4 C. 6 D of 45

42 7.1 Section Quiz. Atoms that tend to gain a noble gas configuration by losing valence electrons are A. metals. B. nonmetals. C. noble gases. D. representative elements. 42 of 45

43 7.1 Section Quiz. When a magnesium atom forms a cation, it does so by A. losing two electrons. B. gaining two electrons. C. losing one electron. D. gaining one electron. 43 of 45

44 7.1 Section Quiz. When a bromine atom forms an anion, it does so by A. losing two electrons. B. gaining two electrons. C. losing one electron. D. gaining one electron 44 of 45

45 Read 7.2 WS 7.1 (Chapter 7 Guided Reading WS due Monday) Make flashcards for the following polyatomic ions: hydroxide, nitrate, acetate, sulfate, carbonate, phosphate, chlorate, ammonium; pg of 45