#nonmetals

Conductivity refers to a material's ability to allow electricity or heat to flow through it. Metals tend to be very good conductors. This has to do with the outer shell of electrons and their ability to freely dissociate from the rest of the atom.

Notice that each of these metals have less than 4 valence electrons (electrons in the outer most shell or ring on the diagrams). All of these can easily move and transport an electrical or thermal current.

Silicon and carbon have four valence electrons making them semiconductors. Their valence electrons are a little more tightly bound to the atom making it harder for them to move. Modifications to semiconductor crystal structures can allow them to conduct better.

Elements like oxygen and phosphorous have more than four valence electrons. This binds them tightly to the atom and does allow freedom of movement. We call these insulators.

To get an electrical current, electrons need somewhere to move. Many simple experiments use copper and zinc because they are neighbors on the periodic table with copper being slightly more electronegative than zinc (it really wants zinc's electrons). Electrons flow from negative to positive while the electrical current flows from positive to negative.

Things change about for nonmetals when it comes to heat conduction because it has less to do with valence electrons and more to do with the vibrations of the atomic lattice. This typically means that they conduct better at higher temperatures (unless they are high-quality crystal). Diamonds are some of the best thermal conductors out there because of their highly ordered crystal structure. However, it is an electrical insulator.

Heat moves in one of three ways: conduction, convection, or radiation. Conduction is the transfer of heat from a warmer material to a cooler one.

Convection is the movement of heat through a fluid (liquid or gas).

Radiation is heat energy transferred through electromagnetic waves.

That's all for now on conductivity. Tomorrow starts our new topic: Igneous Rocks. Tune in to learn about a famous igneous petrologist who revolutionized the study of igneous rocks. Fossilize you later!

1. C / carbon

2. P / phosphorus

3. N / nitrogen

4. H / hydrogen

5. S / sulfur

6. I / iodine

7. Br / bromine

8. Cl / chlorine

9. O / oxygen

10. F / fluorine

.

-- made of one or more cations paired with one or more anions

-- usually the cations are metals and the anions are nonmetals

-- metals tend to lose electrons

-- nonmetals tend to gain electrons

-- when a metal and nonmetal combine, one or more electrons transfer from the metal to the nonmetal

-- this creates positive and negative ions that are attracted to each other

-- we can assume a compound made of a metal and a nonmetal is ionic

-- basic unit is the formula unit      -- smallest electrically neutral collection of ions      -- do not exist as discrete entities but part of a larger three-dimensional array