Elements: A Closer Look Chapter 12 Elements: A Closer Look

Properties of Metals Worksheet  Metals ¾ of all known elements Solid at room temp (NOT Mercury) Low IE = give up electrons Metallic bonds Delocalization Malleable, ductile

Alkali Metals Alkali Metals Video React with not only water, but many other substances Do not find in elemental state Sodium and potassium Relatively abundant nerve impulses Your body would not function correctly w/out these Ion imbalance effects

Alkaline earth metals Alkali and Alkaline Earth Metals Video Denser, harder, higher melting & boiling Less reactive Still not found in elemental form Magnesium and calcium most abundant Magnesium is the most important Alloys Calcium most commonly CaCO3 Seashells, limestone Hard Water

Aluminum Earth’s crust Commercial production Aluminum Video

Transition Elements Reactivity In nature Hardness & melting/boiling points Color Magnetism LAB: Colorful Transition Metals

Uses of Transition Metals Copper Coins – nickel and penny *Electrical conductor Water transport Silver Photographic film Alloys Different properties (chemical and physical) than individual metals Increased strength, hardness Lower electrical and thermal conductivity Lower melting point

Properties of Alloys (Cont) Lower electrical conductivities result because impurities block the path of e- in the electron sea Impurities (in this case, C) occupy the spaces between atoms This makes the alloy stronger because atoms cannot slide past each other Fe C Lower melting points result due to imperfect crystalline structure

Metalloids Properties of both metals and nonmetals Silicon Nonmetallic structure and chemical behavior Luster Conduct electricity Not as well as metals = semiconductors Silicon Metallic luster, but diamond structure Most common metalloid Quartz

Metalloids as Semiconductors Remember: Silicon is poor conductor Certain impurities increase conductivity As small as 1 : 1,000,000!! Called doped crystals Impurities affect silicon in two ways N-type P-type Junctions: n-type next to p-type

Nonmetals - Carbon Distribution Allotropes

Nonmetals – Nitrogen Family Natural occurrence Reactivity Nitrogen cycle 2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O N2 + 8H+ + 8e- + 16 ATP  2NH3 + H2 + 16ADP + 16 Pi

Nitrogen Family (cont) Phosphorus White phosphorus Reactivity Physical properties toxicity Red phosphorus

Nonmetals – Oxygen Family Abundance Reactivity Cellular respiration O3 allotrope Sulfur Industrial

Nonmetals – Halogens and Noble Gases Diatomic Reactivity Halogens Video

Nonmetals - Noble Gases Helium Neon Argon Krypton Xenon Radon