Metals

• Most elements are metals. 88 elements to the left of the stairstep line are metals or metal like elements.

Physical Properties of Metals:

• Luster (shininess) • Good conductors of heat and electricity • High density (heavy for their size) • High melting point • Ductile (most metals can be drawn out into

thin wires) • Malleable (most metals can be hammered

into thin sheets)

Chemical Properties of Metals:

• Easily lose electrons (cations)• Corrode easily• React with acids

Nonmetals

• Nonmetals are found to the right of the stairstep line. Their characteristics are opposite those of metals.

Physical Properties of Nonmetals:

• No luster (dull appearance) • Poor conductor of heat and electricity • Brittle (breaks easily) • Not ductile • Not malleable • Low density • Low melting point

Chemical Properties of Nonmetals:

• Tend to gain electrons (anions)

Metalloids

• Elements on both sides of the zigzag line have properties of both metals and nonmetals. These elements are called metalloids.

Physical Properties of Metalloids:

• Solids • Can be shiny or dull • Ductile • Malleable • Conduct heat and electricity better than

nonmetals but not as well as metals

Alloys

• A homogeneous mixtures of two or more metals

• Also known as a “solid solution”• The mixture is made by melting each metal,

combining the metals, and cooling the mixture and to form a solid.

• Higher or lower density– Rust resistant (aka: oxidation resistant)

• Properties of alloys are frequently far different from those of their constituent elements– Stronger or weaker

Examples of Alloys:

• Steel – iron, manganese, and carbon(adding chromium – slows the rusting process, but it makes it more brittle) – used for cars and plane parts, kitchen utensils fixtures, architecture

• Stainless steel – mixture of iron, nickel, and chromium – Kitchen utensils

• Gold jewelry – gold, copper, and silver

• Sterling silver – silver and a small amount of copper

• Brass – copper and zinc – used for plumbing, light fixtures, ships

• Bronze – copper and tin – harder than brass• Copper and Nickel Alloy – 90% Cu /10% Ni alloy requires no surface

protection and hence gives extra safety, this alloy is being increasingly employed for brake and hydraulic suspension systems and cooling systems in cars and commercial vehicles.

• Aluminum alloy - The most common foil alloys - the 1000, 3000 and 8000 series - contain between 0.5% and 1.5% iron, 0.1% and 0.7% silicon and 0.02% to 1.5% manganese. Up to 0.2% copper may be added when additional strength is required

Purpose of Alloys

• Design of rockets, spacecraft, and aircraft– materials need to be light weight, very strong, and

able to sustain very high temperatures– alloys with aluminum, beryllium, and titanium

• Prosthetic implants– bombarding titanium with nitrogen

• Amalgams – mercury with other metals – old fashioned way of filling a cavity was with

mercury and silver

• Car parts – rims, brakes, shocks• And many others….can you think of any?

• Element Research Project

Periodic Table

Group or Family– Vertical column on the periodic table– Have similar properties– Group A elements have the same charge– Group B elements are transition elements

Period– Horizontal row– 7 periods on the periodic table

Dmitri Mendeleev

• organized the elements based on their properties and increasing atomic mass (1869)

• Predicted properties for elements that were not discovered yet Ekasilicon for Germanium

Periodic Law

• the properties of the elements repeat in a regular manner

Henry Mosley

• reorganized the periodic table based on atomic number (1913)

Properties used to organize the periodic table

Atomic Mass – average of the masses of the isotopes that make up the element and their abundance (amu)

Density – ratio of mass to volume (g/cm3)

Melting Point – temperature at which a solid is in equilibrium with the liquid phase (Kelvin)

• Atomic Radius – Distance from the center of an atom’s nucleus to its outermost electron (nanometer nm)

• Ionization Energy – energy needed to remove one electron (kilojoules per mole kJ/mole); Form a positive charge; Metals like to form cations – low energy

Electronegativity – ability of an atom to attract an electron (no units) Fluorine is the most electronegative atom

Electron Affinity – the energy needed to add/gain one electron; Form a negative charge; Nonmetals like to form anions – low energy