Physical Science

Physical Science Ch. 20

Section 1 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 • Electron Donors • combine with nonmetals by losing electrons

Metallic Bonding • 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

The Alkali Metals • softer and more reactive than other metals • Highly reactive w/ oxygen & water • don’t occur naturally as elemental forms • Combine readily with other elements due to single electron in outer energy level • Located in 1st column of periodic table

Uses of Alkali Metals • Human health • sodium, potassium, and lithium compounds • Photocells • some depend on rubidium or cesium • Francium • a radioactive element which breaks down giving off particles and energy

The Alkaline Earth Metals • not found naturally in elemental form • two electrons in outer energy level • Located in the 2nd column of the periodic table

Alkaline Earth Metals • The Applications • strontium and magnesium found in fireworks • magnesium in vehicles, ladders, and bats • calcium in statues and countertops • Uses with the Human body • calcium in bones • barium in disease diagnoses • radium formerly used in cancer treatments

Transition Elements • They often occur in nature as uncombined elements • Located in the sunken in area of the periodic table • The number of valence electrons have a tendency to vary (transition) at times

Transition Elements • Typically form colored compounds • chromium is in rubies & emeralds • Iron triad (iron, cobalt, and nickel) • Iron • most widely used of all metals • main ingredient in steel • abundant in Earth’s crust • Cobalt and nickel • used in some steels • Nickel • used to coat other metals

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 • Zinc and cadmium • often used to coat or plate other metals • Mercury • only room temperature liquid metal • used in thermometers and batteries

Inner Transition Metals • Rare earth elements • seem disconnected from the rest of periodic table • The Lanthanides Series (1st row) • The Actinides (2nd row) • All are radioactive and unstable • Uranium is the best known

Section 2 Nonmetals

Nonmetals • Properties of nonmetals • Gases or brittle solids at room temperature • Not malleable • Not ductile • Poor conductors of heat and electricity • Lustrous • Electron acceptos

Compounds formed by Nonmetals • Ionic compounds • form when nonmetals gain electrons from metals and become negative ions • Covalent compounds • form when nonmetals share electrons with other nonmetals

Sublimation • a solid changes directly into a gas without first becoming a liquid • Diatomic molecule • two atoms of the same element in covalent bond

Magnificent Seven • 7 diatomic elements • Always occur with 2 atoms • Bromine • Oxygen • Fluoride • Iodine • Nitrogen • Chlorine • Hydrogen

More about nonmetals • Hydrogen • most common element in universe • diatomic molecule • Highly reactive element found mostly on Earth as part of water compound

More about nonmetals • The Halogens (7th column) • A salt forms when a halogen gains one electron from a metal • Use of halogens • Chlorine • disinfectant and bleach • Bromine • dyes in cosmetics • Iodine • hormone regulation

Noble Gases • Exist as isolated, stable atoms • Located in 8th column • Have complete outer energy level filled • Helium • used in blimps and balloons • Neon, argon, and krypton • used in lights

Section 3 Mixed Groups

Properties of metalloids • Located around the stair steps • Form ionic & covalent bonds • Have some metallic & some non-metallic properties • Partial conduction gives them semiconductor characteristics

Boron Group • Named for the first element in 3rd column • Has 3 valence electrons • Boron • used in water softening products, antiseptics, and fuels • Aluminum • abundant in Earth’s crust • used in cans, foil wrap, pans, building materials, and aircraft

Carbon Group • Named for first element in 4th column • Four valence electrons • Carbon • found in coal, oil, natural gas, and foods • Silicon • Occurs as an allotrope • same element with different molecular structures • Found in sand, rocks, and soil • The main component in semiconductors • conduct electricity under certain conditions

Carbon Group con’t • Germanium • also used in semiconductors • Tin • used to coat other metals • Lead • toxic, so no longer used in paint • Allotropes of carbon • Diamonds • Graphite • Buckminsterfullerene

Nitrogen Group • Named for first element in 5th column • Has five valence electrons • tends 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 their melting points

Oxygen Group • Named for first element in 6th column • Has six valence electrons • Oxygen • makes up 20% of air • is used by living things in respiration • provides protection from Sun’s radiation • Sulfur • used to form sulfides for pigment in paint • Selenium • used in photocopiers and multivitamins

Synthetic Elements (man made) • Created 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 americiun • used in smoke detectors. • Transuranium elements • have more than 92 protons • are synthetic and unstable

The study of synthesized 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.

Physical Science