Education.com
Try
Brainzy
Try
Plus

Metals Help (page 2)

By — McGraw-Hill Professional
Updated on Aug 28, 2011

Inner Transition Metals

The 30 elements of the inner transition elements are divided into two groups and called the actinide and lanthanide series.

The actinide series are difficult to isolate since they are highly unstable and experience radioactive decay. They also show a number of oxidation states. Uranium, for example, has compounds in each of the +3, +4, +5, and +6 oxidation states.

The lanthanide elements have electron configurations within the 4f and 5d energy levels. At these high energy levels, electron configuration is fairly theoretical. The lanthanides form 3+ ions as they go into an ionized state. It is assumed that ions are formed by losing the 6s 2 and 5d 1 (or 4f if 5d is not present) electrons. These metals are very similar to each other in their chemical properties. The lanthanide metals are shiny and are affected by water and acids.

Metalloids

Metalloids are elements that have the properties of both metals and non-metals. Metalloids are also referred to as “semi-metals” and are located on the stair step borderline of the Periodic Table between metals and non-metals. The metalloids are made up of boron, silicon, germanium, arsenic, antimony, tellurium, and polonium.

Silicon, the second most abundant element in the Earth’s crust after oxygen, is found in granite, quartz, clay, and sand. At its most basic form, silicon has the same crystalline structure as a diamond. Maybe that is why when you walk along the beach and the sun is high, grains of sand seem to glisten like diamonds!

Silicon is used in semiconductors to carry an electrical charge. Silicon’s natural conducting capacity is further increased when small amounts of arsenic or boron are added to it. Arsenic has one more valence electron than silicon and when it is mixed with silicon, this extra electron wanders around the crystal unattached and able to conduct electricity.

Figure 12.2 shows the location is metals and metalloids in the Periodic Table.

Metals Metalloids

Fig. 12.2. Metalloids are found at the dividing line between metals and non-metals.

Non-metals

Put simply, elements that are not metals are non-metals. Non-metals are found at the far right-hand side of the Periodic Table and consist of only eighteen elements (counting from hydrogen with the non-metals to the right). Six of these elements are the noble gases in group VIII in the far right column. Non-metals are generally gases or solids that do not conduct heat or electricity well. Some non-metals, like diamonds (a stable crystalline form of carbon), are very hard and unreactive, while others, like chlorine, have free electrons and are more reactive. Non-metals are not lustrous and are not malleable or ductile. Eleven of the non-metals are gases, one is a liquid, and six are solids. Figure 12.3 shows non-metals in solid, liquid, and gaseous forms.

Metals Non-metals

Fig. 12.3. Non-metals are found in all three forms of matter, liquid, solid, and gas.

Non-metals are described as elements without metallic properties. They are poor conductors of heat and electricity and are not magnetic like iron.

Noble gases are non-metals and exist as individual atoms such as neon and argon. Other non-metals are two-atom molecules, such as hydrogen, nitrogen, and oxygen.

Fluorine is at the top of the column (VIIA) in the Periodic Table known as the halogens or “salt formers.” Chlorine, bromine, iodine, and astatine are also in the halogen group. Halogens easily accept electrons from other atoms and combine with metals to form salts. In nature, fluorine is found in ores of fluorspar (calcium fluoride) and cryolite (a combination of sodium, fluorine, and aluminum). In the body, fluorine is found in the blood, bones, and teeth. Many communities in the United States add small amounts of fluorine to drinking water, since the presence of fluorine has been found to prevent the formation of cavities in teeth.

View Full Article
Add your own comment