Periodic Trend Atomic Radius

Atomic radius refers to the size of an atom. It is defined as one-half the distance between between two nuclei in a chemical bond. Atomic radius is measured in picometers. 1 picometer is a trillionth of a meter. 1 pm = 10-12 meters. Atomic radii range from 32 pm, the atomic radius of helium, to…

Continue Reading →

Periodic Trends and Coulomb’s Law

Periodic Trends describe repeating patterns that help predict certain properties, depending on an element’s location in the Periodic Table. In this section, I will discuss the periodic trends of atomic radius, ionic radius, ionization energy, electronegativity and electron affinity. In order to better understand Periodic Trends, it is best to explore Coulomb’s law, which describes…

Continue Reading →

Semi-Metals or Metalloids

The semi-metals, also known as metalloids, are Boron (atomic number 5), Silicon (14), Germanium (32), Arsenic (33), Antimony (51), Tellurium (52) and Polonium (84). They are so named because they share properties of both metals and nonmetals. As such, they tend to be lustrous (like metals), brittle (as opposed to the malleability and ductility of…

Continue Reading →

Inner Transition Metals

The Inner Transition Metals are also referred to as Rare Earth Metals. These elements are mainly radioactive, because of their large size, and elements beyond uranium (atomic number 92) are human-made. This elements beyond atomic number 92 are often referred to as the transuranium elements.

Continue Reading →

Transition Metals

The Transition Metals are those elements in groups 3 through 12 on the Periodic Table. They share the properties of all metals, those of malleability, ductility and conductivity. Their highest energy electrons can be found in the “d” sublevel, which allows them many different oxidation states (an oxidation state is another term for the charge…

Continue Reading →

The Alkaline Earth Metals

The alkaline earth metals are found in the second group of the Periodic Table (IIA).   As their name suggests, they are metals, so they possess properties common to all metals, such as malleability, ductility and conductivity. Overall though, they are less metallic in nature than the alkali metals, as metallic character decreases as you…

Continue Reading →

The Alkali Metals

The first group on the left of the Periodic Table, Group 1 (IA) is known as the Alkali Metals. The alkali metals are highly reactive metals that do not exist by themselves in nature. They are highly reactive because they have just one valence electron, which they can easily give up to form an ionic…

Continue Reading →

Structure of the Modern Periodic Table

The Modern Periodic Table is arranged in order of increasing atomic number, which is the number of protons in the nucleus of an atom. The lightest atom is Hydrogen, in the upper left-hand corner, with an atomic number of 1. This means that hydrogen contains only 1 proton in its nucleus. The heaviest naturally occurring…

Continue Reading →

History of the Periodic Table

The Greeks were the first to float the idea that matter was composed of elements. Aristotle believed these elements to be Earth, Fire, Air and Water, whilst Democritus theorized an atomic theory of matter — that all matter was composed of indivisible units or “atomos.” (”Atomos” means indivisible). Antonie Lavoisier in the 1700s was the…

Continue Reading →