CHEMISTRY - CLUTCH CH.22 - CHEMISTRY OF THE NONMETALS.

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2 CNCEPT: YDRGEN CEMISTRY The hydrogen atom represents the simplest of the elements of the Periodic Table and consists of proton and electron Elemental hydrogen will react with elements to form either ionic or covalent hydrides. Ionic ydrides When reacting with Group 1A elements, the heavy Group 2A elements:, or and other reactive metals. These compounds tend to be white, crystalline solids. 2 K (s) + 2 (g) Ba (s) + 2 (g) The hydride ion can also act as a agent and donate its electrons or as a base. SiBr3 (l) + Na (g) Cl (aq) + Na (g) Covalent ydrides When reacting with nonmetals. o 3 2 (g) + N2 (g) 2 N3 (g) Δ Rxn = 91.8 kj Page 2

3 CNCEPT: ALKALI METALS Named for the solutions they tend to form during reactions. Because of their lower molar masses, larger atomic radii and ns 1 electron configuration they tend to be malleable with densities, melting and boiling points. Because they are strong reducing agents they naturally occur as cations in nature. Reacting with 2 Almost all the Alkali Metals are water soluble and create highly heat of hydration ( Δ hydr ). In the process the hydrogen is. 2 M (s) (l) 2 M + (aq) + 2 (aq) + 2 (g) Reacting with 2 The Alkali Metals react with elemental oxygen to form different types of. Li (s) + 2 (g) Na (s) + 2 (g) M (s) + 2 (g) Reacting with alogens The Alkali Metals react with the diatomic halogens to form. 2 M (s) + X2 ( X = F, Cl, Br or I ) Page 3

4 CNCEPT: ALKALINE EART METALS Named because their oxides also form basic solutions and because their high temperatures allowed them to remain as a solid ( earth ). Physical Properties Their higher temperature is the result of an additional valence electron: ns 2 electron configuration. The addition of the valence electron with a minimal change in size results in metallic bonding. Chemical Properties All the Alkaline Earth Metals except for form ionic compounds when bonding to nonmetals. Page 4

5 CNCEPT: REACTINS F ALKALINE EART METALS Reacting with 2 Since they can act as strong agents they can reduce atmospheric oxygen. 2 M (s) + 2 (g) Reacting with 2 The heavy Group 2A elements:, or reduce water to form elemental hydrogen. M (s) (l) M 2+ (aq) + 2 (aq) + 2 (g) Reacting with alogens The Alkaline Earth Metals react with the diatomic halogens to form. M (s) + X2 ( X = F, Cl, Br or I ) Page 5

6 Elemental xides All Alkaline Earth Metal oxides are basic with exception to. M (s) + 2 (l) M 2+ (aq) + 2 (aq) Thermal Decomposition Carbonate compounds will undergo thermal decomposition to form the oxide. M3 (s) Page 6

7 CNCEPT: PERIDIC TRENDS F METALS are similarities that exist between a Period 2 element and another element that is diagonally lower one level and to the right. Lithium & Magnesium Both react with elemental nitrogen to form. Li (s) + N2 (g) Mg (s) + N2 (g) Both form hydroxides and carbonates that undergo thermal decomposition. Beryllium & Aluminum Both form oxide coatings that prevent reaction with water. Both form oxides that are. Boron & Silicon Electrical they behave as. In their oxyacid or oxoacid forms they represent. 3 B 3 Boric Acid 2 Si 3 Metasilicic Acid 4 Si 4 Silicic Acid When combined with a hydride ion they represent. B 3 Borane Si 4 Silane Page 7

8 CNCEPT: TE BRN FAMILY Although boron is at the top of Group 3A, it does not represent the general properties of the group because it is sole metalloid. Physical & Chemical Behavior Element Bonding Melting Point ( o C) Δ Fusion (kj / mol) B Al Ga In Tl Nh* N/A N/A N/A * was formally called. Physical Properties - Although the trends are not as uniform throughout Group 3A, we can say generally the boiling points and densities when going down the group. xidation States - The state is the most common form experienced by this group, but as we move down the group the state becomes more predominant. - The lower oxidation state of elements tend to be more than the oxides with the element in a higher oxidation state. Page 8

9 CNCEPT: BRN FAMILY CEMISTRY The periodic trends of Group 3A are harder to predict as a result of the inclusion of d and f electrons as we move down the group. These irregularities as a result impact the chemical properties of elements. Chemical Properties - Boron is the only metalloid in Group 3A and is reactive at room temperature and only forms bonds. - Aluminum forms oxides and when connected to halogens in the gas phase it forms covalent dimers. - All remaining elements in the group form ionic bonds, however they do contain more covalent character than Group 2A. Reactions Elements within this group react very slowly or not at all with water: In the presence of oxygen gas and heat they become oxides: When placed next to halogens they undergo oxidation: Page 9

10 CNCEPT: TE CARBN FAMILY The column containing carbon is unique in that it contains all 3 classifications for elements:, and. Physical & Chemical Behavior Element Bonding Melting Point ( o C) Δ Fusion (kj / mol) C Si Ge Sn Pb Fl* N/A N/A N/A * was formally called. Allotropism Allotropism is the ability of some elements to exist in different forms while in the same physical state. Carbon for instance has two predominate forms: and. Their differences in form can lead to vastly different properties. is represented as a soft, black conductor of electricity, while is considered one of the hardest natural materials in nature that is colorless and is an insulator of electricity. A 1980s mass spectroscopic examination of soot discovered another allotropy for carbon known as buckminsterfullerene, or simply. Page 10

11 CNCEPT: CARBN CEMISTRY Carbon is one of the most unique elements of the periodic table because of its ability to form covalent bonds with other carbon atoms in a process called. By incorporating other nonmetals it is possible to create diverse organic compounds found in nature. C C C C C C C Ethanol Cinnamic aldehyde Acetic Acid As you move down the group the atomic radius, which creates longer bonds that are weaker and more open to reactions. As a result none of the other elements form stable chemical chains. Gaseous xides Inorganic carbon compounds are commonly found with carbonates. CaC3 (s) + 2S4 (aq) Carbon monoxide, C, represents another gaseous oxide that is commonly used in industrial production of methanol and methanal. It also plays a disruptive effect in displacing oxygen from hemoglobin. C alomethanes Carbon can form strong chemical bonds with halogens to form (CFCs), which have been linked to deterioration of the ozone layer. F Cl C Cl F Page 11

12 CNCEPT: TE SILICN CEMISTRY The chemistry of silicon is dominated by the formation of bonds. These long repeating chains can be formed naturally into what are called silicates or synthetically created into other structures called silicones. Silicates The building block unit for silicates is the, which is represented by Si4 4-. Si rthosilicate ions rthosilicate complex Silicones Within these structures we have two hydrocarbon groups connect to each silicon atom and those silicon atoms are connected to one another by an oxygen atom. C 3 C 3 C 3 C 3 Si Si Si Si C 3 C 3 C 3 C 3 The of the silicones are held by weak intermolecular forces and so experience increased flexibility, while the gives rigidity and stability to the compound. Page 12

13 CNCEPT: TE NITRGEN FAMILY Due to its position on the periodic table Group 5A shows more diversity than the earlier groups. Physical & Chemical Behavior The non-predictable behavior of the elements in Group 5A reflects the transition from individual covalent molecules in and to network covalent solids in and to the metallic characteristics of and. Element Bonding Melting Point ( o C) Δ Fusion (kj / mol) N P As Sb Bi Mc N/A N/A N/A * was formally called. Allotropism Phosphorus (P4) - form is made of individual tetrahedrons, giving them low melting points and high solubility in nonpolar solvents. Reactivity. - form exists in chains; making them have higher melting points, lower solubility in nonpolar solvents. Reactivity. Page 13

14 CNCEPT: TE XYGEN FAMILY Since the structure and organization of Group 6A mirrors that of Group 5A there will be many similarities between the two. Group 5A Group 6A Similarities N P As Sb Bi Nh S Se Te Po Lv * was formally called. Allotropism xygen (2 Major Forms) - represents the more stable, safe form and is colorless as well as odorless. - represents the more hazard form and is bluish in color, while possessing a strong smell. Sulfur (More than different forms) - The most stable allotrope is. S S S S S S S Selenium (Se, Se2, Se6, Se8 & Se10 ) S Tellurium (2 Major Forms) - Amorphous tellurium, which is either a blackish or dark grayish color. - Crystalline tellurium, which possesses a hexagonal shape. Page 14

15 CNCEPT: TE ALGENS The halogens, elements in Group 7A, represent the last reactive group on the periodic table. The halogens exist as diatomic molecules:,,, &. The final slot of the group belongs to, which was previously named. Physical & Chemical Behavior The halogens display predictable trends in their physical properties. Intermolecular force:. As we move down the group there is a (n) in the strength of these intermolecular forces. Group 7A Bond Length (pm) Bond Energy (kj/mol) Physical Features F F Cl Cl Br Br I I xidation States xidation State: The oxidation state is the most common and all the halogens except for can obtain all the odd-numbered states from to. alogens react exothermically with one another to form interhalogen compounds. Ex: alo-oxyanions xyanion ypohalite alite alate Perhalate Fluorine Chlorine Bromine Iodine * In basic solutions halogens form hypohalites and at elevated tempeatures it can form halates. Page 15