By Kevin Beck, Updated Aug 30 2022

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What Are Elements?

In chemistry, an element is a substance composed of atoms that all contain the same number of protons. An element cannot be broken down into simpler substances using conventional chemical methods. As of 2018, scientists have confirmed 92 naturally occurring elements, plus 11 synthetic isotopes that appear only under laboratory conditions. Each element exists in one of three physical states—solid, liquid, or gas—under standard conditions.

Atoms are tiny clusters of protons, neutrons, and electrons. Hydrogen, the simplest, contains one proton and one electron, whereas uranium’s most common isotope has 92 protons, 92 electrons, and 146 neutrons. Protons carry a positive charge; electrons carry an equal negative charge; neutrons are neutral. The balance of protons and electrons determines an element’s identity, while variations in neutron count produce isotopes.

The Periodic Table of Elements

The periodic table is the cornerstone of modern chemistry, arranging all known elements by ascending atomic number—the count of protons in the nucleus. This ordering reveals repeating patterns of chemical behavior, hence the name “periodic.” While the table has 113 entries (118 as of 2023), elements are grouped into families that reflect shared properties.

When you examine the table, you’ll notice that the upper rows contain gaps—these are elements that have not yet been discovered or synthesized. The layout incorporates columns (groups) and rows (periods) that reflect electron configuration and reactivity.

Periodic Table Groups

Historically, elements are divided into three broad categories: metals, nonmetals, and metalloids. Nonmetals are limited to seven core elements—hydrogen (H), carbon (C), nitrogen (N), oxygen (O), phosphorus (P), sulfur (S), and selenium (Se). Additional nonmetal families include the halogens (F, Cl, Br, I, At) and the noble gases (He, Ne, Ar, Kr, Xe, Ra). Metalloids, such as silicon and arsenic, exhibit intermediate characteristics.

Characteristics of Metals

Out of the 113 elements, 88 are classified as metals. Despite their diversity, metals share several hallmark traits:

• Solid at room temperature (except mercury, a liquid metal used historically in thermometers).
• Luster—a shiny surface that reflects light, contributing to their aesthetic and economic value.
• Malleability—the ability to be hammered or rolled into thin sheets without cracking.
• Ductility—the capacity to be drawn into wires, a key property for electrical and thermal conductors.
• High density—most metals have a high mass per unit volume.
• Elevated melting and boiling points—for instance, tungsten’s melting point is 3422 °C, making it indispensable for incandescent light bulb filaments.

Types of Metals

Metals are further categorized into five main groups:

• Alkali metals (six elements in group IA: Li, Na, K, Rb, Cs, Fr).
• Alkaline earth metals (six elements in group IIA: Be, Mg, Ca, Sr, Ba, Ra).
• Transition metals (forty elements spanning groups IIIB–XII, rows 3–6).
• Lanthanides (elements 58–71, also known as rare‑earth metals).
• Actinides (elements 90–103, a subset of the rare‑earth family).
• Unspecified metals (eight elements that do not fit neatly into the above categories).

Adding these groups together gives a total of 88 metals: 6 alkali + 6 alkaline earth + 40 transition + 28 rare‑earth + 8 unspecified.

Metalloids and Nonmetals

Metalloids occupy a niche between metals and nonmetals, combining conductive properties with semiconductor behavior. The seven common metalloids are:

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

These elements are solid at room temperature and play crucial roles in modern electronics, often forming alloys with metallic elements to tailor electrical and thermal characteristics.

For an interactive exploration of the periodic table, visit our resources page.

Key Takeaways

• Metals comprise the majority of elements, with 88 out of 113 on the periodic table.
• They are characterized by luster, malleability, ductility, density, and high melting points.
• The primary metal families—alkali, alkaline earth, transition, lanthanide, actinide—each have distinct chemical behaviors.
• Metalloids bridge the gap between metals and nonmetals, underpinning semiconductor technology.