Metallic Bonds and Properties of Metals

Metals do not actually donate their valence electrons form lattices in the solid state where each metal atom is surrounded by 8- 10 neighboring atoms

Valence Electrons outer energy levels overlap in metals valence electrons are not held by any particular metal atom move easily from atom to atom delocalized electrons This is called the electron sea model

Vocabulary Word Electron Sea Model: metal atoms contribute their valence electrons to form a “sea” of electrons.

Vocabulary Word metallic bond: attraction of a metallic cation for delocalized electrons

Properties of metals - Melting Point metals have high melting points mercury is a liquid at room temperature used in barometers and thermometers tungsten has a melting point of 3422 degrees used in light bulbs and spacecraft parts

Properties of metals - Boiling Point in general metals have high boiling points it takes a great deal of energy to separate the cations and electrons

Properties of metals - Malleable metals can be hammered into sheets mobile parts of metallic bonds allow cations and delocalized electrons to slide past each other so metals are malleable and ductile delocalized electrons can shift allowing metallic bonds to remain intact

Properties of Metals - Durable metals are durable because the metallic cations are mobile within the metal, but strongly attracted to the electrons not easily removed strength and durability increase as the number of delocalized valence electrons increases

Properties of Metals - Conductors metals are good at conducting heat and electricity charged electrons are able to move heat and charge from one place to another quickly

Properties of Metals - Luster delocalized electrons can interact with light so they reflect light absorb and release photons (particles of light) and appear shiny

alloy: mixture of elements that has metallic properties Vocabulary alloy: mixture of elements that has metallic properties

Alloys brass = mostly copper with 10-30% zinc bronze = mostly copper with some zinc and tin 10 carat gold = 40% gold, 20% silver, 40% copper stainless steel = 75% iron, 15% chromium, 10% nickle

Hypothesis vs theory A hypothesis is an attempt to explain phenomena.  It is a proposal, a guess used to understand and/or predict something.  A theory is the result of testing a hypothesis and developing an explanation that is assumed to be true about something.  A theory replaces the hypothesis after testing confirms the hypothesis, or the hypothesis is modified and tested again, until predictable results occur. So, a person might make an observation and immediately form a hypothesis about why something happens the way it does.  He or she then tests the hypothesis, modifies it if necessary, and eventually develops a theory. The hypothesis might change significantly as testing occurs. A hypothesis can be right or wrong, but a theory is supposed to be true based upon the scientific method.  So, when a hypothesis has been verified to be true, it becomes a theory. A theory has not been proven to the point is has become a law

The Quarter!!  The total composition of the coin is 8.33% nickel, with the remainder copper. It weighs 5.670 grams .  How many grams of nickel does a quarter contain? How many atoms? How many grams of copper does a quarter contain? How many atoms? Fact: It currently costs 11.14 cents to produce each quarter as of 2011.

Composition of Limestone Limestone is by definition a rock that contains at least 50% calcium carbonate by weight Assume you have a 45.6g limestone sample that is 62.4% calcium carbonate. What is the mass of the calcium carbonate? How many calcium carbonate particles do you have? How many oxygen atoms do you have?