The Periodic Table of Elements

An element is a basic substance that can’t be broken down into simpler substances. Think of it like the simplest building block of matter. Each element is made up of just one kind of atom, like gold is made only of gold atoms, and oxygen is made of oxygen atoms. There are over a hundred different elements, and they each have their own properties—some are metals, some are gases, some react easily with other elements, and some don’t. When elements combine, they form all the different materials and compounds we see around us, like water, which is made from hydrogen and oxygen.

What is the periodic table of elements?

The periodic table of elements is a chart that organizes all known elements based on their properties. It’s like a map for understanding the building blocks of matter. Each element has a specific place in the table, arranged by its atomic number, which is the number of protons in its atoms. The table is divided into rows and columns that group elements with similar characteristics, like metals, non-metals, and gases. This organization helps scientists quickly see patterns in how elements behave, predict reactions, and understand how different elements interact to form everything around us.

How was it made?

The periodic table was created in 1869 by a Russian chemist named Dmitri Mendeleev. He arranged elements by their atomic weights and noticed that certain properties repeated in a pattern. Mendeleev left gaps for elements that hadn’t been discovered yet, predicting that they would be found to fit into those spaces, which later proved to be true. Over time, scientists refined the table to be organized by atomic number (the number of protons in an atom) instead of atomic weight, which made it even more accurate. The periodic table has since become a vital tool in chemistry, helping scientists understand elements and how they relate to one another.

How is an element structured?

An element is structured at the atomic level, meaning it’s made up of tiny particles called atoms. Each atom of an element has three main parts: protons, neutrons, and electrons. The protons and neutrons are found in the center, or nucleus, of the atom, giving it most of its mass. The electrons move around the nucleus in regions called shells or orbitals. The number of protons in the nucleus defines what element it is—like hydrogen has one proton, while carbon has six. The arrangement of electrons around the nucleus influences how the element will interact with other elements, forming the basis for chemical reactions and bonds.

What is the "staircase"?

The staircase line on the periodic table helps show the difference between metals and nonmetals. It starts between boron (B) and aluminum (Al) and zigzags down to separate elements with metallic properties from those that don’t. Elements that are right next to this staircase are called metalloids. Metalloids have a mix of metal and nonmetal qualities. For example, they might look shiny like metals but be brittle and not conduct electricity as well. Common metalloids include boron (B), silicon (Si), and arsenic (As). On the left side of the staircase are metals, which are usually shiny, can conduct electricity, and are easy to shape. On the right side are nonmetals, which aren’t good conductors and can be solid, liquid, or gas.

Element Key

How are elements organized on the periodic table?

In the top left of the element you will see the number, "1". This number means that the element, Hydrogen, is the first element placed on the periodic table.

Next, in the middle of the element you can see the letter, "H". The "H" stands for Hydrogen, and "H" is it's chemical symbol.

Bellow you will see the name of the element, which in this case is Hydrogen.

And lastly, at the bottom of the element there is the atomic mass. The atomic mass is how much the atom ways at an atomic level. Hydrogen's atomic mass is 1.008.