We all know and use the periodic table. This icon of chemistry classrooms has many versions. The chemistry community is celebrating the table’s 150th anniversary this year. You can see the latest version of it here: https://iupac.org/what-we-do/periodic-table-of-elements/ . If you would like to know more of its history, see https://www.sciencenews.org/article/periodic-table-history-chemical-elements-150-anniversary.
All elementary and higher classrooms need to have this chart. I recommend that you start with a simple version that has the elements’ symbol, name, and atomic number but little else. That’s enough information for beginners. The color scheme should make it easy to tell the metals, metalloids, and the nonmetals apart. Samples of some common and safe elements will help children see the significance of this chart.
My card set, “Discovering the Periodic Table”, helps children find out why the elements are arranged as they are on the periodic table. You can see more about at https://big-picture-science.myshopify.com/collections/physical-science/products/discovering-the-periodic-table.
I like to tell children that if they meet an alien from another planet, they could communicate via the periodic table because the chemical elements are present throughout the universe. We can tell this by the unique wavelengths of light that each element gives off.
After children are familiar with a simple periodic table, they may find a chart that illustrates the elements attractive. These charts vary in quality, and most are confusingly busy. Make sure that an illustrated chart shows something that is meaningful to children or that it shows the actual element. Vague scenes or unfamiliar objects are not likely to help children grasp the concept of elements.
There is another chart for chemistry that is very useful for advanced elementary and middle school levels. It is the classification of matter chart. If you search the Internet for “classification of matter chart,” you will find many flow charts. Big Picture Science offers the chart from InPrint for Children, which I helped design. This chart shows the chemical forms that matter can take. First, it divides matter into pure substances and mixtures. It has four photo cards with information on the back for each of four categories – elements, chemical compounds (both are pure substances), and homogeneous and heterogeneous mixtures.
This chart has information that children need to imagine the kinds of atoms or molecules that may be in a substance. They see how chemical elements are a part of all matter and how elements combine in compounds. Most matter that they encounter is some sort of mixture. The chart will help them sort out the major types of mixtures as well.
The photos show four common elements that you can have as samples in the classroom – zinc, copper, sulfur, and silicon. The latter is available from scientific supplies as the lump form, laboratory grade. Be sure to get the lump or crystalline form. This element is also sold in a powder form, but this doesn’t allow children to see the shiny crystals.
Enjoy exploring the chemical elements and ordering them on the periodic table and the classification of matter chart!
Last June, the organization that officially recognizes the discovery of chemical elements and their names announced the proposed names for the final four elements on the periodic table. This governing body, the International Union of Pure and Applied Chemistry (IUPAC), took suggestions from the discoverers of the elements and then it issued the proposal. People could submit comments about the names for several months, and then in November, the IUPAC published the names. This was the final step in making them official.
The element names and atomic numbers are: nihonium (Nh) for element 113, which is named for the country of Japan; moscovium (Mc) for element 115, named for Moscow, Russia; tennessine (Ts) for element 117, named for the state of Tennessee; and oganesson (Og) for element 118, named after a Russian scientist who helped discover several elements, Yuri Oganessian. A new periodic table with these names is available at the IUPAC website, https://iupac.org/what-we-do/periodic-table-of-elements/ .
So what does this mean for the Montessori classroom? Children are ready for the abstract idea of chemical elements when they are in their elementary years. When they get an introduction to the periodic table, it should include the full set of names. Children should get a least a brief story of how elements get their names and how governing bodies of science fields bring order to science knowledge.
Children need to know, however, that there are elements that one cannot see with one’s eyes. There are quite a number of elements that are known only by the energy, particles, and atoms produced when they undergo radioactive decay.
The image below is from my newly updated card set, Discovering the Periodic Table. It comes with two sets of cards for all 118 elements, one in color and one in black and white. The card on the left is an example of the color set, and in this case sodium's symbol is color-coded red to show it is one of the alkali metals. The other card is the back of the black and white card, and it shows the type of information given for each element - physical properties, chemical properties, and other information. The front of the black and white card is like the card on the left, but with the symbol only outlined.
I updated and expanded Discovering the Periodic Table last summer after the new names were announced. At that time I added some features to help children understand the nature of the largest elements. The elements that cannot be made in visible quantities have symbols with a dotted outline rather than a solid one. The smallest of these is astatine, atomic number 85. Scientists have calculated that if one could make a piece of astatine, it would instantly vaporize itself because of the energy released by its vigorous radioactive decay.
If you tell children this, they may wonder how such an element was ever discovered. If they don’t think of it, help them arrive at this question. We want children to think about what they hear and ask about how we know what we know. The idea to search for astatine came from its place in the periodic table. Mendeleev left a blank beneath iodine on his first periodic table, implying that there was another element in the halogen family. Researchers that first identified this element used a nuclear reactor to bombard bismuth, atomic number 83, with alpha particles. This added two more protons to bismuth nuclei, and produced a small amount of astatine, which quickly decayed. Later, when researchers knew astatine’s characteristics, and they were able to find tiny traces of it in uranium ores.
After astatine, the next element that can’t be made in visible amounts is francium, atomic number 87. The dotted outline symbols don’t show up again until atomic number 101, mendelevium. It and all larger elements cannot be made in visible amounts. Researchers have made so little of elements 104-118 that the chemical properties of these elements are also unknown. In the cards with color-coded symbols from Discovering the Periodic Table, elements 104-118 have gray symbols to show that there is not enough evidence to assign them to a chemical group such the halogens.
Your children may ask if more elements can be discovered. In theory there could be, but if someone does discover more elements, it will be bigger science news than any recent element discovery. Meanwhile, help 6-9 year-olds explore the common everyday elements with the cards set, Elements Around Us from InPrint for Children. The set, Element Knowledge, will help 9-15 year-olds learn element names, symbols, and several significant groups. This set includes the first 111 elements. You can add the names and symbols of the other seven if your children are interested. They certainly won’t see those symbols in any chemical formulas.
We have a few more of the periodic tables with magnetic tiles from InPrint for Children, so I’ve added it to my product listings. I helped design this periodic table several years ago, guided by the principle of “isolate the difficulty.” Each tile has only an atomic symbol and the atomic number that goes with it. The background color of the tiles codes for metals, metalloids, and nonmetals. Hydrogen gets its own color as a reflection of its special role in the universe. With this simplified periodic table, children can see the big patterns of chemical elements before they have to deal more advanced periodic tables with their overwhelmingly busy look. When you look at this periodic table with all the tiles in place, you will likely be struck by the number of metals versus nonmetals. Five of the six main elements of life are nonmetals, and you see that nonmetals are a small fraction of the total elements. Children will also see the state of matter of each element at room temperature from the border around the square where the tile goes. With enough heat, all would be gases. With enough cold, all would be solids, but it would take near absolute zero for that to happen. Children enjoy constructing this periodic table several times, and they learn the location of elements as they do so. They can learn the element names when they refer to the table that comes with this set. The table also shows the origin of each element, whether it was formed by the Big Bang, by cosmic rays, in the center of stars, during supernova explosions, or synthesized in laboratories.
In its present production, this periodic table is printed on a heavy-weight magnet-receptive vinyl. It needs to be mounted on a rigid backing material. Suggestions for backing materials come along with the teacher’s background information. I mounted my own on white board material, and then added a narrow wooden frame to secure the edges. This arrangement has survived several trips to conferences, teacher education programs, and workshops.
Coupled with samples of a few metals, sulfur, carbon, and silicon - safe substances for children to handle, this material is a great way to introduce children to the chemical elements.