This activity is a fun way to get your students to familiarize themselves with the elements of the Periodic Table and their symbols. There are many opportunities for extending this activity, and it is a chance to engage students who enjoy word games in a science activity.
The longest word you can make is a favorite "longest word" of mine. I have seen this word in use in one of Patrick O"Brian's Master and Commander novels. The word is floccinaucinihilipilification, and it can be spelled using the abbreviations of the elements.
This activity walks students through finding element symbols useful for forming words and provides tables for organizing their findings. The first table includes room for all of the single-letter symbols. These are the easiest to use. In the second table, students record all of the symbols that include vowels, also very useful. The final table is for recording two-consonant symbols that the students anticipate might come in handy, like Bromine (Br) but not Berkelium (Bk). After organizing the symbols that may be most useful, students can refer to their tables for help forming words.
It is beneficial to be working with an up-to-date periodic table that includes the three elements recognized in 2011. They are Darmstadtium (Ds), atomic number 110, Roentgenium (Rg), atomic number 111, and Copernicum (Cn), atomic number 112. You may also find one that includes two elements recognized in 2012, Flerovium (Fl) and Livermorium (Lv). Four more elements were recognized in January 2016, and these have yet to be named or given symbols. When they are, feel free to include them.
There are many possible extensions to this activity. Of course, there is researching the addition of new symbols to the table. You could also discuss how scientists knew that there were elements missing. By observing the ways in which elements combine, they were able to determine the number of protons in known elements and recognize where undiscovered elements should be. They were then able to extrapolate and identify elements of the greatest number of protons. These are highly unstable and exist only under laboratory conditions. The book The Disappearing Spoon, by Sam Kean, is a fascinating look at the history of the periodic table and elements. I highly recommend it. It is an easy read and will provide you with many stories and anecdotes for your students during a study of chemistry. In addition to identifying as many words as possible, you can also challenge students to find the word with the greatest combined atomic number.
Be sure to find Tom Lehrer's Element Song online. The kids will love it. I have included a transcript of the lyrics. In the past I have had the students learn the song and sing it at an assembly. The elements are not in order in the song, and it doesn't have much utility, but it is fun. It does not include any recently discovered elements, but maybe you could have your kids sing an addendum?
I do not have the rights to a specific Periodic Table, but many are available online for use, and you may have one in a text. I have included an answer key with many of the possible words. I am not a Scrabble player, and I am sure there are other “words” that can be found, but I have included many for you to share with the students after they have given this activity a try.