Education.com
Try
Brainzy
Try
Plus

The Periodic Table Help (page 2)

based on 1 rating
By — McGraw-Hill Professional
Updated on Aug 28, 2011

Element Classes

As Meyer reported in his research, some elements with similar properties can be grouped together. Basically, groups of elements are divided into four main classes.

(1) Representative elements (groups IA-VIIA)

(2) Noble or inert gases (group VIII)

(3) Transition metals (group B elements)

(4) Inner transition metals

The representative elements or main group of elements is further defined. Group IA, the alkali metals (e.g., lithium, potassium), are all soft metals (except hydrogen, a gas) that react readily with water. Group IIA, known as the alkaline earth metals (e.g., beryllium, cadmium), are also reactive chemically. The halogens , in group VIIA, are all non-metals. Chalcogens , group VIA (e.g., oxygen, sulfur), comes from the Greek word chalkos meaning ore. Many ores are made with varying amounts of oxygen and sulfur. The remainder of the representative element groups (IIIA-VA) have not been given descriptive names.

The noble or inert gases (group VIII) are called inert since they seldom form chemical compounds. In fact, helium, neon, and argon refuse to play with anyone and don’t form any compounds at all. All these gases exist naturally as individual atoms in the environment.

The transition metals (group B) contain the more recognizable metals. They are used in construction, coins, and jewelry. The transition metals group includes iron, nickel, and chromium as well as gold, silver, and copper.

The inner transition metals consist of the 15 rare earth metals or lanthanides. They are all silvery white in color and used in such products as permanent magnets and headphones. The other inner transition metals, a set of elements named after the element actinium, include uranium, americium, and neptunium. They are primarily human-made elements. These metals are radioactive and used in advanced smoke detectors, neutron-detection devices and in nuclear reactions.

Metals Vs. Non-metals

It is important to observe that metals and non-metals are shown on the Periodic Table by a heavy zigzag line with metals to the left side and non-metals to the right. Figure 4.5 shows this dividing line.

Most metals are shiny and good conductors of heat and electricity.

Metals , about 80% of the elements, can be pulled into thin wires (ductile) or pounded into sheets (malleable). Mercury is the only metallic element that is liquid at room temperature.

Elements, Symbols, and the Periodic Table Metals Vs. Non-metals

Fig. 4.5. There are a lot more metals than non-metals.

Non-metals are basically everything else. Most are gases such as helium and argon, or brittle solids such as phosphorus and selenium. Bromine is the only liquid, non-metallic element at room temperature.

The elements found along the borderline of metals and non-metals are known as semi-metals or metalloids since they have the characteristics of both metals and non-metals. For example, silicon is used to make lubricants, computer circuits, and medical implants and joints.

If asked to learn only one thing in all of chemistry, pick the Periodic Table. Learn it and all the rest will fall into place.

Practice problems for these concepts can be found at - The Periodic Table Practice Test

View Full Article
Add your own comment