The post-transition metals cluster to the lower left of this line.

Many periodic tables will feature a bolded 'staircase' line below the diagonal connecting boron with astatine. These elements have some of the classic characteristics of the transition metals, but they tend to be softer and conduct more poorly than other transition metals. The post-transition metals are aluminum (Al), gallium (Ga), indium (In), thallium (Tl), tin (Sn), lead (Pb) and bismuth (Bi), and they span Group 13 to Group 17. Post-transition metals: Ahead of the jump into the nonmetal world, shared characteristics aren't neatly divided along vertical group lines. Many of the greatest hits of the metal world - including gold, silver, iron and platinum - live here. Hard but malleable, shiny, and possessing good conductivity, these elements are what you typically think of when you hear the word metal. Transition metals: Returning to the main body of the table, the remainder of Groups 3 through 12 represent the rest of the transition metals. The actinides and the lanthanides together form a group called the inner transition metals. Of these elements, only thorium (Th) and uranium (U) occur naturally on Earth in substantial amounts. The elements in this group have a silvery white color and tarnish on contact with air.Īctinides: The actinides line the bottom row of the island and comprise elements 89, actinium (Ac), through 103, lawrencium (Lr).

This is the lanthanides, elements 57 through 71 - lanthanum (La) to lutetium (Lu). Lanthanides: The third group is much too long to fit into the third column, so it is broken out and flipped sideways to become the top row of the island that floats at the bottom of the table. Their chemical reactions typically occur more slowly and produce less heat compared to the alkali metals. But they're not as reactive as the alkali metals. Each of these elements has two electrons in its outermost energy level, which makes the alkaline earths reactive enough that they're rarely found alone in nature. Hydrogen, with its single electron, also lives in Group 1, but the gas is considered a nonmetal.Īlkaline-earth metals: The alkaline-earth metals make up Group 2 of the periodic table, from beryllium (Be) through radium (Ra). They are also extremely reactive and will burst into flame or even explode on contact with water, so chemists store them in oils or inert gases. Shiny and soft enough to cut with a knife, these metals start with lithium (Li) and end with francium (Fr). It's thought that another one of these magic numbers lies just beyond the range of currently known elements, which means we could potentially discover some new elements that are relatively stable and extremely massive.The periodic table of elements is arranged into several broad groups (Image credit: Future) Groups of the Periodic tableĪlkali metals: The alkali metals make up most of Group 1, the table's first column. There are believed to be certain numbers/ratios that are inherently more stable. Hence, larger atoms become more unstable. The ratio of neutrons to protons gradually increases to try to compensate, but this results in the neutrons getting more unstable themselves, resulting in more opportunity for weak forces to destabilize them. With all of that to consider, as you get larger and larger nuclei with more protons, the electromagnetic forces increase, as well as the distances in the nuclei, putting more strain on the nuclear forces holding it all together. Neutrons will help add to this nuclear force, but they tend to become unstable when they get into too great of concentration and the weak force will cause them to decay into protons. Fusion allows these protons to get close enough together for the stronger, yet short ranged, nuclear force to overpower the electromagnetic force. The electromagnetic force of the protons wants to push them away from each other.

There are several forces at work inside the nuclei of atoms.

Chemical elements with a