Metals 8-4 to And you

Characteristics Malleable: Metals can be hammered into shapes or thin sheets Ductile: Metals can be stretched into thin wires

b. positive core of atoms can slide past each other and still be held together by the ____________________ Cool Sea of electrons

Bonding described as a “sea of electrons” ~ delocalized or spread out electrons are free to move around the positive nuclei of the metal. This model explains many of the properties of metals: malleable, ductile, and conductive. The delocalized electrons can “carry” or transfer heat and/or electricity around and through the cations of the metal. Metals also display shine or luster, as the delocalized electrons reflect incident light.

Metals usually have low ionization energies, since the valence electrons are few in number and far from the nucleus. An excellent example of this is Group 1, the Alkali Metals. Very reactive, these metals are never found alone in nature, but in compounds. To isolate the metal, electrolysis is needed: 2NaCl  2Na + Cl 2

As you move down the Alkali group, the reactions of the metals (with oxygen, water, etc.) become more rapid and violent, since the valence electrons are farther from the nucleus (lower IE). Also, down the group melting and boiling points go down (Cs melts in your hand).

Reactions of Metals: think of water as HOH *memorize these please !!!!!!!!!!! 2Na (s) + 2HOH (l)  2NaOH (aq) + H 2(g) Na 2 O (s) + HOH (l)  2NaOH (aq) (Metallic oxides in water make base) 2Na (s) + Cl 2(g)  2NaCl e- moves from Na to Cl

Transition metals ancient metals: Au, Ag, Hg, Cu, Sn, Fe, Pb

Properties of Transition Metals (in addition to those of typical metals): 1) Form colored compounds. 2) Have multiple oxidation states or charges since s and d electrons can be lost. 3) Many are used as catalysts. 4) Some used in creating alloys.

So what is this “alloy” of which you speak???? An alloy is a mixture of two or more elements where the major component is a metal. Most pure metals are either soft or chemically reactive. The goal of making an alloy is to increase the strength and resistance to corrosion. Common alloys: Steel = Fe + CBrass = Cu + Zn

Why do the characteristics of the metals change?? It simply messes with the flow of things

2 types of alloys Substitutional: Host metal atoms are replaced by other metal atoms. Combo of properties example: Copper and Zinc to form Brass Interstitial: Small atoms occupy the spaces (holes)between the host metal atoms example: Iron and Carbon to form steel Big change in properties (soft to hard)

8-5 Metalloids

The metalloids are elements located on either side of the zig-zag staircase (with the exception of Al, which is a metal). Metalloids have some characteristics of metals and some of nonmetals since their ionization energies and electronegativites are between those of metals and nonmetals. Some of the metalloids (Si and Ge) are semiconductors, meaning they can carry electrical charge under special conditions and making them useful in electronic devices like computers.

Silicon – forms network covalent bonds 4th type of bonding – e-s being shared but structure is considered one large unit – very strong structure – diamond, Si structure similar Some call it a mega molecule but technically it is not a molecule because the number of atoms is variable depending upon the size of the crystal