Chapter 6 Notes. Section 4-5 Nonmetals

Transcription

1 Chapter 6 Notes Section 4-5 Nonmetals

2 Section 4-5 Objectives 8) Contrast the reactivity and abundance of elements in the Group 3A through Group 8A. 9) Name an important element in each group of p-block elements and describe its uses. 10) List several sources of hydrogen on Earth. 11) Describe the main properties of hydrogen.

3 6-4 From Metals to Nonmetals: p-block

4 6-4 From Metals to Nonmetals: p-block p-block is made of both metals and non-metals Most important elements: Aluminum, carbon, silicon, nitrogen, oxygen and chlorine. p-block elements form important compounds used for technology and in nature.

5 The Boron Group: 3A Most abundant element: Aluminum (3 rd most abundant in the Earth s crust) Generally not very reactive. Often found in compounds because pure aluminum is rare to extract. Charles Hall (1886) found a way to inexpensively extract aluminum from it s compounds. Caused aluminum to become affordable and common Aluminum is a useful structural metal: Cans, cookware, foil, automobiles

6 The Carbon Group: 4A Contains nonmetal, semi-metal and metal elements. Carbon: widely distributed through the Earth s crust and is found in all living organisms. More reactive than Boron group. Elemental bonding creates different materials: graphite and diamonds

7 The Carbon Group: 4A (continued) Carbon: Hydrocarbons: are burned as fuels: coal, petroleum and natural gas. are used to make plastics and medicines. when burned, release CO 2. CO2 is used to carbonate soda and when solid = dry ice

8 The Carbon Group: 4A (continued) Silicon: 2 nd most abundant element in the Earth s crust. Found in compounds to form silicates (sand and glass) or used as a semiconductor (transistors and solar cells. Color in glass comes from other d-block elements Germanium, Tin and Lead: Used to make important structural alloys (pipes and plumbing) or in batteries (lead batteries in cars)

9 The Nitrogen Group: 5A Contains nonmetal, semi-metal and metal elements. Nitrogen and Phosphorus are non-metal and the most abundant and important elements in this group. Nitrogen: composes 80% of the Earth s atmosphere. Odorless and colorless Relatively not very reactive (more than 3A and 4A) Usually found and utilized by organisms as compounds. Formation of nitrogen compounds = nitrogen fixation. Used in fertilizers and in as ammonia for cleaning

10 The Nitrogen Group: 5A (continued) Phosphorus: Occurs in all living things. Found in compounds with oxygen (phosphates) Phosphoric acid is used to manufacture fertilizers, detergents and other products. Creates the sour taste in various soft drinks.

11 The Oxygen Group: 6A Oxygen and Sulfur are the most important elements of the oxygen group. Oxygen is the most abundant element on Earth. 23% of the mass of air 89% of the mass of water 46% of the mass of crustal rocks of Earth Pure oxygen is an odorless, colorless and tasteless gas Oxygen reacts with most elements to form oxides. O 3 is known as ozone air pollutant in lower atmosphere In upper atmosphere protects against UV radiation

12 The Oxygen Group: 6A (continued) Sulfur: Often found in its elemental form in nature. Historically called brimstone Forms pyrite (FeS 2 ) : Fool s Gold Compounds with sulfur smell like rotten eggs Sulfur is found in eggs and skunk spray Sulfuric acid is the most widespread used sulfur compound. H 2 SO 4 is used in almost all manufacturing processes.

13 The Halogens: 7A Halogen = salt-former in Greek All halogens exist in elemental form as diatomic (2 atom) molecules. F 2, Cl 2, Br 2, I 2 and At 2 Halogens are very reactive! And do not occur as free elements in nature. They are HUNGRY for electrons! Halogens form 1- ions (halides) Important Halogens: Fluorine, Chlorine, Bromine and Iodine.

14 The Halogens: 7A (continued) Fluorine: Very corrosive gas Naturally occurring in compounds in the Earth s crust. Used to manufacture Teflon and CFCs (chlorofluorocarbons) which are used as refrigerants. Chlorine: poisonous gas but most often found as NaCl. Chlorine is used as a disinfectant and bleach. It is used to manufacture PVC plastic. Chlorine can be hazardous to living organisms.

15 The Halogens: 7A (continued) Bromine and Iodine: Not as abundant as Fluorine and Chlorine. Less reactive as you go down the periods. Fluorine (most reactive) - Iodine (least reactive They are used as fire retardants, pesticides and film. Iodine has other medicinal purposes to treat minor cuts and scratches.

16 The Noble Gases: 8A Noble gases are the least reactive of all elements. Full valence shell Named the Noble gases because they do not form compounds. Some man-made exceptions XeF 6 Most abundant: Argon 1% of the Earth s atmosphere. Most commercially important: Helium refrigerant When electrically excited, most noble gases will lightup Neon lights

17 Hydrogen Hydrogen is located with the alkali metals but does not exhibit similar properties. Belongs with the halogens: similar properties Sources: Most of the Earth s hydrogen is combined with oxygen in the form of water (H 2 O) Found as O2 gas in the atmosphere. Found in many organic compounds.

18 Hydrogen Properties: Odorless, colorless gas that occurs as an H 2 molecule. Uses: The major use is to manufacture ammonia for fertilizer. Also seen as hydrocarbons (fuels) and organic compounds.