Elements and Their Properties Chapter 19 Elements and Their Properties

Metals Properties of Metals Conduct heat and electricity. Luster- reflect light well. Malleable- can be hammered or rolled into sheets. Ductile- can be drawn into wires.

Metals- Cont. Ionic Bonds- combine with nonmetals by losing electrons.

Metals- Cont. Metallic Bonds- positively charged metallic ions are surrounded by a cloud of electrons; ions are in sliding layers and electrons are weakly held; readily form ionic bonds with nonmetals.

Alkali Metals The Alkali Metals- softer and more reactive than other metals. Highly reactive with oxygen and water; don’t occur naturally in elemental forms. Combine readily with other elements due to single electrons in the outer energy level. Alkali Metals are found in Group 1 of the Periodic Table.

Alkali Metals- Cont. - Multiple uses Human Health- Na, K, Li Photocells- some depend on Ru or Cs Francium- a radioactive element which breaks down giving off particles and energy

Alkaline Earth Metals Alkaline Earth Metals- not found naturally in elemental form; two electrons in outer energy level. Alkaline Earth Metals are found in Group 2 of the Periodic Table.

Alkaline Earth Metals Applications- Strontium and Magnesium found in fireworks; Magnesium in vehicles, ladders, and bats; Calcium in statues and countertops Human body- Calcium in bones; Barium in disease diagnoses; Radium formerly used in cancer treatment

Transition Metals Transition Metals- they often occur in nature as uncombined elements Transition Metals are found in Groups 3-12 of the Periodic Table.

Transition Metals- Cont. Typically form colored compounds- Chromium found in rubies and emeralds Chromium in it’s raw form.

Transition Metals- Cont. Iron Triad- Iron, Cobalt, and Nickel Iron- Most widely used of all metals and main ingredient in steel; abundant in Earth’s crust Cobalt & Nickel- used in some steels Nickel used to coat other metals

Transition Metals- Cont. Copper, silver, gold- Coinage metals since once were commonly used in coins Copper- used in electric wiring because it is a superior electricity conductor. Silver- used in photographic film and paper, jewelry Gold- used in jewelry and fillings

Transition Metals- Cont. Zinc, Cadmium, Mercury- Group 12 on the periodic table Zinc & Cadmium- often used to coat or plate other metals Mercury- only room temperature liquid metal; used in thermometers and batteries

Transition Metals- Cont. Inner transition- seem disconnected from the rest of the periodic table Lanthanides- include La, Cr, Pr, Sm, Eu, Gd, Tb Actinides- all are radioactive and unstable; Uranium is the best known Uranium in raw form.

Nonmetals Properties of Nonmetals Usually gases or brittle solids at room temperature Are not malleable or ductile Usually poor conductors of heat and electricity Usually not lustrous

Non Metals- Cont. Ionic compounds form when nonmetals gain electrons from metals and become negative ions. Covalent compounds form when nonmetals share electrons with other nonmetals.

Nonmetals- Cont. Hydrogen- most common element in universe Diatomic molecule- two atoms of the same element in a covalent compound Highly reactive element found mostly on Earth as part of a water compound

Nonmetals- Cont. Halogens- include Bromine, Iodine, Fluorine, Chlorine, and Astatine Halogens are found in group 17 of the periodic table.

Nonmetals- Cont. A salt forms when a halogen gains one electron from a metal Uses of Halogens Chlorine- disinfectant and bleach Bromine- dyes in cosmetics Iodine- hormone regulation Sublimation- a solid changes directly into a gas without first becoming a liquid

Nonmetals- Cont. Noble Gases- exist as isolated, stable atoms Helium- used in blimps and balloons Neon, Argon, Krypton- used in lights

Review Question C12 H22 O11 Number of atoms C= H= O= Total number of atoms:________

Mixed Groups Properties of Metalloids Form ionic and covalent bonds Have some metallic and some nonmetallic properties Partial conduction gives them semiconductor characteristics

Mixed Groups- Cont. Boron Group- named for the first element in Group 13 Boron- use in water softening products, antiseptic, and fuels Aluminum- abundant in Earth’s crust; used in cans, foil wrap, pans, building materials, and aircraft

Mixed Groups- Cont. Carbon Group- four electrons in outer energy level Carbon- found in coal, oil, natural gas, and foods Silicon occurs as an allotrope- same element with different molecular structures Silicon- found in sand, rocks, and soil The main component in semiconductors, which conduct electricity under certain conditions Germanium- also used in semiconductors Tin- used to coat other metals Lead- toxic, so no longer used in paint Diamonds, graphite, and buckminsterfullerene are all allotropes of carbon.

Mixed Groups- Cont. Nitrogen Group- five electrons in outer energy level; trend to form covalent bonds Nitrogen- used to make nitrates and ammonia Phosphorus- used in water softeners, fertilizers, match heads, fine china Antimony and Bismuth- used with other metals to lower melting points

Mixed Groups- Cont. Oxygen or Group 16 Oxygen- makes up 20% of air, is used by living things in respiration, and provides protection from the sun’s radiation Sulfur- used to form sulfides for pigment in paint Selenium- used in photocopiers and multivitamins Te & Po are also oxygen group elements.

Mixed Groups- Cont. Synthetic elements- scientists create elements not usually found on Earth; synthetic elements usually disintegrate quickly Uranium can be made into Neptunium which forms plutonium when it disintegrates Plutonium can be changed into Americum, which is used in smoke detectors. Transuranium have more than 92 protons and are synthetic and unstable The study of synthetic elements helps scientists to understand the forces holding the nucleus together. Element 114 lasted for 30 seconds. It combined 114 protons with 175 neutrons. It broke apart due to enormous repulsion between the protons. ca