Chapter 7 The Elements

I. Properties of s-Block Elements A. Representative Elements Groups 1A through 8A Display a wide range of physical and chemical properties

- Metals and nonmetals - Highly reactive and some that hardly react - Solids, liquids, and gases at room temperature

B. Hydrogen Share more properties with the nonmetals of group 7A than of group 1A Has both metallic and nonmetallic properties so it is not considered part of any group Burns when ignited with air - Hindenburg crashed in 1937 in New Jersey

Colorless, orderless, lighter-than-air gas Three natural occurring isotopes 1. protium: hydrogen-1 (99.985%) 2. deuterium: hydrogen-2 (0.015%) 3. tritium: hydrogen-3 (radioactive)

C. Group 1A: Alkali Metals React with water to form alkaline, or salt, solutions Easily lose a valence electron and form an ion with a 1+ charge Soft enough to cut with a knife Stored in oil to prevent a reaction with oxygen in the air Good conductors of heat and electricity

1. Lithium Least reactive of alkali metals Used for long lasting batteries and as a drug to treat bipolar disorders

2. Sodium and Potassium Most abundant alkali metals Must have in our diets because many biological functions are controlled by sodium and potassium ions - Carries nerve impulses along the cell

D. Group 2A: Alkaline Earth Metals Form compounds with oxygen, called oxides Shiny solids Lose their two valence electrons to form ions with a 2+ charge

1. Calcium Essential in maintaining healthy bones and teeth Found combined with carbon and oxygen in calcium carbonate - Main ingredient in limestone, chalk, and marble Used as an antacid

2. Magnesium Plants cannot function without a supply of magnesium because each chlorophyll molecule contains a magnesium ion Your body needs magnesium in muscle function and metabolism Results in hard water when found in the water supply

II. Properties of p-Block Elements Metals, metalloids, and nonmetals Solids and gases

A. Group 3A: The Boron Group Always found combined with other elements in nature B, Al, Ga, and In lose 3 valence electrons to form ions with a 3+ charge

1. Boron Can withstand extreme differences in temperature without shattering - Good for laboratory equipment and cookware Borax, a cleaning agent and as fireproof insulation Boron nitride is the second hardest known material, only diamond is harder

2. Aluminum Third most abundant element in Earth’s crust Found combined with oxygen and requires a great deal of energy to remove it from oxygen - Cost effective to recycle aluminum products

3. Gallium Used in thermometers because it literally melts in your hand Used in solar panels because it produces an electric current when it absorbs light

B. Group 4A: The Carbon Group Wide range of properties limits the rules that apply to all members of the group

1. Carbon Whole branch of chemistry devoted to the study of carbon compounds – organic chemistry Inorganic chemistry includes carbonates, cyanides, carbides, sulfides, and oxides Two allotropes – graphite and diamond - Allotropes are forms of an element in the same physical state – solid, liquid, or gas – that have different structures and properties

2. Silicon Used in computer chips and solar cells Found combined with oxygen in silicon dioxide which is found in quartz, sand, and glass

3. Lead and tin Lead is toxic and no longer used for eating utensils, pipes for plumbing, as an additive in gasoline, or in paint Tin is a very soft metal Tin Lead

C. Group 5A: The Nitrogen Group Colorless, ordorless, gas Makes up about 78% of Earth’s atmosphere Liquid ammonia is used in cleaning supplies Fertilizers are made with nitrogen

2. Phosphorus Three solid allotropes Red phosphorus is used on the striking surface of matchboxes No longer used in fertilizers because they are harmful to the environment i.e. cause excess algae in lakes

3. Arsenic, Antimony, and Bismuth Arsenic is toxic Antimony can be shaped and cast in molds to make tableware Bismuth is an active ingredient in Peptobismol

D. Group 6A: The Oxygen Group Tend to gain two electrons to form ions with a 2- charge 1. Oxygen Has two allotropes Ozone (O3) is an unstable gas Oxygen gas (O2) makes up 21% of Earth’s atmosphere

2. Sulfur Has ten allotropes Ingredient in fertilizers, steel, papers, and paints

3. Selenium Found in fish, eggs, and grains Works with vitamin E to prevent cell damage Found in locoweed which can sicken livestock Used in solar panels to convert light into electricity

E. Group 7A: The Halogens “Salt formers” Reactive nonmetals that are always found combined with other elements in nature Tend to gain one electron to form ions with a 1- charge

1. Fluorine Most electronegative element on the periodic table - Has the greatest tendency to attract electrons - Reacts with every element except helium, neon, and argon Added to toothpaste and drinking water to protect tooth enamel from decay

2. Chlorine Used to disinfect sewage and as a bleaching agent Hydrochloric acid in your stomach helps you digest food

3. Iodine Body needs iodine to maintain a healthy thyroid gland to help control growth and metabolic rates Iodine tablets are used to disinfect water

F. Group 8A: Noble Gasses Colorless and unreactive Known for their stability

1. Helium Lighter-than-air gas Used in blimps, airships, and balloons 2. Neon Used in light displays - Produces an orange light when its excited electrons return to lower energy states

3. Argon and Krypton Argon makes up 1% of Earth’s atmosphere Both are used in incandescent light bulbs

III. Properties of d-Block Elements Transition metals Labeled “B” Any element whose final electron enters a d sublevel Differ in physical properties

A. Formation of ions Can lose two s electrons to form an ion with a 2+ charge Elements with unpaired d electrons can form ions with a 3+ or higher

B. Magnetism Ferromagnetism is a strong attraction of a substance to a magnetic field - Ions align themselves to the direction of the field - Iron, cobalt, and nickel can form permanent magnets

Diamagnetism is when a substance is either unaffected or slightly repelled by a magnetic field - Element’s electrons spin in opposite directions, causing their magnetic fields to cancel out

C. Sources of transition metals Copper, silver, gold, platinum, and palladium are the only transition metals stable enough to be found in nature uncombined with other elements Most others are found as compounds with nonmetals in ores that can be mined and extracted

D. Uses of transition metals Many are found in alloys used to make items such as jet engines, drill bits, surgical instruments, and armor Many are trace elements needed by your body Some are included in vitamin and mineral supplements

IV. Inner Transition Metals Any element whose final electron enters an f sublevel A. Lanthanide series Elements from period 6 are named the lanthanide series because they follow the element lanthanum

Silvery metals Found mixed together and are hard to separate Neodymium and praseodymium absorb high-energy radiation so they are used in welder’s goggles Yttrium and europium are found in television screens and computer monitors

B. Actinide series Elements from period 7 are named the actinide series because they follow the element actinium Radioactive elements Three exist in nature, the rest are synthetic