The color-coded periodic table is a tabular representation of the different chemical elements. Elements in the periodic table can be color-coded together according to atomic number, electron configuration, and recurring chemical properties. Because there are a number of ways to classify the elements, there exist a number of color-coding schemes we could use to point out specific properties that groups of elements share in common.
One of the most common ways of grouping elements in the periodic table are groupings based on general element-type, such as by the categories, metal, nonmetal, and metalloid.
What Is The Periodic Table?
First some general facts about the periodic table. Each cell in the periodic table has a symbol for the element, the atomic number of the element which corresponds to the number of protons in an atom of that element, and the average atomic weight of that element. The periodic table is organized in a matrix of horizontal rows and vertical columns called periods and groups, respectively. Elements in arranged in a period exhibit recurring chemical properties as you go from left to right. For example, elements on the leftmost part of the rows have few exterior electrons in their outer shells, and the number increases as you go from left to right.
“What the ocean was to a child, the periodic table is to the chemist.” — Karl Barry Sharpless
These periodic changes correspond to periodic changes in the chemical behavior of elements as you go along the row. The result is the elements that are arranged in the same groups share similar chemical properties. For example, carbon is in the same group as silicon as they both exhibit similar chemical properties. Both carbon and silicon have 4 open valence electrons, which explains why they exhibit similar chemical properties. Similarly, both fluorine and chlorine are halogens and are characterized by their tendency to spontaneously form strong ionic bonds with electronegatively weak elements.
Now that we have some basics of the periodic table under our belt, let’s move on to specific ways to organize the chemical elements.
Color-Coded Periodic Table By Element Type
In the above photo, the elements are color-coded respective to the general type of substance that element falls under. In general, chemists divide the elements into three major types: metals (purple) non-metals (blue) and metalloids (green). Although these categories are commonly used, classifications at the edge have somewhat fuzzy boundaries. For example, in some cases, arsenic would be classified as a metal due to its strong conductive properties. In other cases, arsenic is classified as a metalloid as it is brittle at room temperature and readily dissolves in water. These fuzzy boundaries merely reflect the fact that there is no universal agreement about which elements fall within these categories, but in general, scientists work with this general understanding of the division of element-types.
Elements classified as metals are unified by their tendency to form cations, enter into metallic chemical bonds with other metals, are prone to oxidization, and are generally good conductors of heat and electricity. Metals represent the largest classification of element-type as approximately 95 of the 118 discovered elements are metals.
When metal elements form compounds, their bonds are characterized by the delocalization of electron pairs. In other words, a metal compound can be thought of as a positively charged lattice of cations that shares electrons freely across its structure. The chemical nature of metallic bonds explains many of the unique properties of metals, such as their strength, durability, luster, and conductive properties. The category of metals can be further divided into ferrous (magnetic) and non-ferrous metals, Alkali, transition, and base metals, and so forth. Depending on which specific properties of metals are of interest to the researcher, they will classify them into different subgroups.
In simplest terms, a nonmetal on the periodic table is an element that mostly lacks any metallic properties. Non-metals generally have low melting and boiling points, are usually brittle at room temperatures, are poor conductors of heat and electricity, and typically enter into covalent or ionic bonds with other elements.
Nonmetals can be further divided into two categories: noble gases and reactive nonmetals. Noble gases, which constitute the left-most group of the periodic table and include elements such as Neon or Argon are characterized by their chemical inertness. Noble gasses are chemically inert because they have a full valence shell of electrons and thus have a very stable electron configuration. Reactive nonmetals, as the name would imply, refers to any nonmetals that readily react with other elements. Less electronegative nonmetals, like carbon or sulfur, are disposed to form covalent bonds by sharing electrons. More electronegative nonmetals, like oxygen, or the halogens (group 7) are much more reactive and readily form strong ionic bonds with metals.
“Wonder is the heaviest element on the periodic table. Even a tiny fleck of it stops time.” — Diane Ackerman
Occupying the middle portions of the periodic table are the sparsely populated metalloids (semimetals). As the name would imply, metalloids exhibit a unique mixture of metallic and non-metallic properties, such that metalloids do not fall clearly into either metal or nonmetal categories. The six most commonly recognized metalloids are boron, silicon, arsenic germanium, antimony, and tellurium. Like metals, metalloids exhibit a characteristic luster and are generally fair conductors of heat and electricity. Like nonmetals, metalloids are usually brittle at room temperatures and generally form covalent bonds with other elements.
One of the most important kinds of metalloids is silicon, a semiconductor that has formed the backbone of the modern electronics industry. Silicon is a relatively cheap and abundant natural material that exhibits strong conductive properties at room temperature and makes an ideal conductor to use in modern electronics.
There are a number of other ways to organize elements on the periodic table. You can organize elements by their electronegativities, their binding properties, their capacity to dissolve in solvents, ionization energy or their electron orbital configuration. Organizing by general element type merely represents one way that chemists have attempted to catalog the wide range of nature’s chemical elements.