Metalloids in the Periodic Table

Metalloids are elements from the periodic table with properties that lie between metals and non-metals. The following ScienceStruck article will cover some information related to metalloids.

The first person to come up with a periodic table of elements was Dmitri Ivanovich Mendeleev, a Russian chemist. He came up with the first version of periodic table in 1864. Mendeleev’s table was based on the atomic weight of the elements. He found that there were many elements that shared similar properties and occurred periodically. Thus, he came up with the concept of periodic table of elements. His table had been divided into three main sections – metals, nonmetals, and metalloids. In this article, we shall concentrate on the metalloids from the periodic table.

According to Mendeleev’s law of periodic table, the chemical and physical properties of elements vary in a periodic fashion according to their atomic weights. However, the modern periodic table of elements follow the law that, the properties of elements vary according to their atomic number and not by their weight. The elements of a Mendeleev’s table were arranged in rows called periods and columns called groups. The chemical elements of the same group had similar properties. There are different regions in the periodic table that are called periodic table blocks, as they are named according to the subshell of the last electron of the atom.

The metalloids, also known as semi-metals, are placed between metals and non-metals in the periodic table of elements. There are seven elements that are classified as metalloids and placed in Group 13, 14, 15, 16, and 17. They are found in a stair step line that helps differentiate metals from non-metals in this element table. The line that separates metalloids from the metals and non-metals in the periodic table is called amphoteric line.

As mentioned above, there are 7 elements in the periodic table that exhibit metalloid behavior. They occur in a diagonal line from boron to astatine through the p-block. The elements in the upper-right portion of the line show increasing non-metallic behavior and the elements at the lower-left of the line show increasing metallic behavior. The list of metalloids in the periodic table are as follows:

• Boron (B)
• Silicon (Si)
• Germanium (Ge)
• Arsenic (As)
• Antimony (Sb)
• Tellurium (Te)
• Polonium (Po)

The term metalloid comes from the Greek word metallon, which means ‘metal’, and edios, meaning ‘sort.’ The metalloids are often seen forming amphoteric oxides, and they behave as semiconductors. They have properties of both metals and non-metals in the periodic table. They even carry electric charge that makes them suitable for use in computers and calculators. Their ionization energy as well as electronegativity values are between those of metals and non-metals. Their reactivity depends on the metals that they are reacting with.

As you can see in the periodic table, there is a line that distinguishes boron and aluminum to the border seen between polonium and astatine. However, aluminum is classified under ‘other metals’. The element carbon is a non-metal, but graphite displays limited conductivity, which is the characteristic of a metalloid. Silicon and germanium exhibit properties of a semiconductor. When boron reacts with sodium, it acts as a non-metal, whereas in case of reaction with fluorine, boron exhibits metallic properties.