Understanding the Periodic Table

Human beings have interacted with elements since prehistoric times. Yet large-scale efforts to organize these elements did not come about until the 19th century. In this lesson, become acquainted with the periodic table. Learn about its basic organizing principles and allow Ron to take you on a quick tour of its evolution through time.

The periodic table was a collaborative effort that spanned centuries. In this lesson, dig deeper into its early history. Learn about debates surrounding the classification and categorization of elements, and explore how the discovery of subatomic particles, specifically protons, propelled a specific version of the periodic table to the forefront.

What gives the modern periodic table its distinctive shape? The answer: electrons. Understand the relationship between an atom’s nucleus and its electrons, then discover how these peculiar subatomic particles—that do not always behave like particles—determine the number and type of bonds an element can make.

What constitutes a “group” of elements? Are neighboring groups similar in some way? And beyond proton counts and electron valences, what other chemical and physical characteristics govern the structure of the periodic table? Better understand how the periodic table brings together elements with similar properties from the size of their atomic radius to their electro-negativity.

Here, grasp how just three elements—hydrogen, helium, and lithium—combined to create new, heavier elements like uranium or sulfur through the complicated process of nuclear fusion. Also discover how natural and cosmic events like supernovas can lead to the creation of new elements through time.

A cosmic event is not the only way an element can transform. The processes of transmutation, radiation, and nuclear fission are equally capable of radically altering elements and their behaviors. Familiarize yourself with the ever-important process of transmutation and learn how elements with unstable nuclei break down to produce more stable products through radiation and nuclear fission.

Shifting gears, spend some time on the first and smallest row of the periodic table. Consider some important questions: What do two of the oldest, lightest elements—hydrogen and helium—have in common? How do they differ? And would they make sense somewhere else on the periodic table, given their particular characteristics and behaviors?

Despite the abundance of lithium, sodium, potassium, rubidium, and cesium in the environment, researchers did not isolate alkali metals until the 1800s. Here, focus on the elusive elements that make up the first column and major group of the periodic table and understand what led to their discovery and why they are so quick to combine with other elements.

After the alkali metals come the alkaline metals, a slightly less reactive group of elements. In this lesson, explore the characteristics of group two metals like calcium, strontium, and barium, and figure out why they oxidize slower and melt at higher temperatures than the alkali metals.

What exactly stitches the p-block of the periodic table together? In this lesson, get acquainted with the metals, metalloids, and nonmetals of the p-block, a collection of diverse elements that stretches from row two to seven of the periodic table. Take a detailed walk through the chemical and physical characteristics, distinguishing behaviors, and common uses of p-block elements.

Discovered in the 19th century, noble gasses stupefied chemists; these elements react poorly with themselves and other chemicals. Explore the history behind noble gasses starting with Argon, understand the conditions and methods that led to their discovery, and become familiar with the basic properties and behaviors of these unique gaseous elements.

Group 17 contains some of the most reactive elements on the periodic table. As you explore this group, become familiar with the halogens, a group of elements quick to combine with metals to form salts. Learn about each element in the group from most reactive to least and explore the unique set of properties that define each halogen on the table.

Among a sea of 118 elements, many of them novel and poorly understood, oxygen and nitrogen stand out because they are familiar to us. But what do we really know about their discovery, behaviors, and subatomic structures? And what can the periodic table reveal about their abundance in Earth’s atmosphere? Answer these questions and more.

In the final set of nonmetal elements on the periodic table, diversity abounds. These elements do not behave like most nonmetals in that some can conduct electricity, form solids under standard conditions, and can exhibit a range of allotropes. Spend this lesson exploring the subatomic peculiarities and behaviors of carbon, phosphorus, sulfur, and selenium.

Between the metal and nonmetal groups, you will find a third and more peculiar group: the metalloids. What specific properties—subatomic and beyond—do they share with metals, and how do they behave like nonmetals? Unearth the history behind the discovery of metalloids and learn why they are so useful when they combine with other elements.

p-Block metals are faced with an identity crisis as they behave like metals and nonmetals at the same time. But why is this the case? Get to know the “weak” metals and why they behave the way they do. Understand how the electron configurations of elements like gallium and lead affect their behavior, discover what sets p-block elements apart from the metals of the d-block, and more.

The valley at the middle of the periodic table features one-third of naturally occurring elements—all of which are metals. What do they have in common and what sets them apart? Take an introductory tour of the d-block metals from the poisonous to the ultra-dense before spending the next few lessons exploring three groups of transition metals in detail.

What makes precious gemstones so colorful? The answer: a group of metals from the d-block of the periodic table. Begin with a focus on the early transition metals of the d-block. From vanadium to rhenium, consider the distinct geometries of their subshells, walk through their everyday uses, and understand the complexities of their oxidation states.

Iron is Earth’s most abundant element while platinum and other noble metals are among its most stable. Learn about the history, fundamentals, and uses of the periodic table’s precious metals. Move from the iron triad to the platinum group of elements and discover how this set of d-block “noble” metals changed the way we fuel the world’s automobiles.

Coinage metals look like other group VIII elements, but they also possess some properties reminiscent of alkali and alkaline metals. In this lesson, complete the d-block by delving into copper, silver, gold, zinc, cadmium and mercury. Explore the special subatomic qualities that made these metals so hard to categorize and discover what they are typically used for.

It may be surprising that rare-earth elements are not all that uncommon compared to other elements on the periodic table. Instead, their most distinctive feature is a common geochemistry. Here, focus on how rare-earth elements and the so-called “lanthanide contraction” trend spurred substantial technological advancements in lighting, electronics, headphones, and more.

At the very bottom of the periodic table, you will find some of its most radioactive and unstable elements. Now, turn to the seventh row and spend some time with the most abundant pair of “light” actinoids—uranium and thorium—and learn how instability and radioactive decay have come to define this group of elements.

The discovery of the neutron in 1932 was a germinal event in the history of science. Soon after, scientists discovered how the combination of neutrons and naturally occurring elements can create new elements that cannot and do not exist in nature. Continue your exploration of the bottom of the table by focusing on the finding, features, and functions of the transplutonic elements.

In this lesson, turn to the very end of the periodic table and delve into the so-called “superheavy” elements. Learn about the contentious Cold War history behind row seven of the periodic table and how the quest to complete the table moved from politically fraught to internationally collaborative.