An easy way to remember the first 20 elements is to use a mnemonic, such as H. Helen Little Beryl Brown Chews Nuts On Friday Neights, NaMgAl SiPS Chlorine After Kissing Caboys. The first two letters of each of the words corresponds with the elements on the table.
The first 20 elements are hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, flourine, neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon, potassium and calcium. Of these elements, 12 have symbols that correspond to the first one or two letters of the name, but the rest may have different letters that correspond to them. For example, the periodic symbol for potassium is K. The majority of symbols are made up of a combination of the first letter and one middle letter. The first 20 of the elements that are on the table are among the most common elements that are found throughout the universe and are some of the most important elements in the entire system.
The system for writing the elements is dependent on what the element is. Gaseous and ionic molecules are written differently and according to the type of gas or ion they contain. Elements can attach to each other and often do so to form compounds. These compounds list how many units of each element there are and organize the elements in order from the strongest to the weakest in the compound.