Diatomic ElementS
Some elements cannot exist by themselves, even when they are isolated from any other type of atom. Elements of this nature will combine with atoms of the same element in order to be stable.
In other words, hydrogen, a diatomic element, cannot be by itself. It cannot exist as simply H. Hydrogen is so reactive that when isolated from everything but hydrogen it will combine into a diatomic (two atom) molecule. Therefore, hydrogen gas, that is sometimes used as a fuel, exists as H2.
These elements are diatomic ONLY when they are alone, NOT when chemically bonded to another atom. When hydrogen is bonded to something other than itself, the numbers of hydrogens depends on the charge of the other atom.
There are eight elements that form diatomic molecules, that cannot exist by themselves. They are high-lighted on the periodic table below. They are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine and astatine.
There are eight elements that form diatomic molecules, that cannot exist by themselves. They are high-lighted on the periodic table below. They are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine and astatine.
To help you remember them, there are three helpful phrases. Pick the one that you can relate to:
1) “7 that make a 7 and hydrogen” (Starting at element number 7, make a seven by going over 2 elements, and down 4 elements. Those you just went over are the diatomic element -- you’ll just have to remember hydrogen.)
OR (2) “GEN-u-INE” (If the element’s name ends in -gen or -ine, it is diatomic when by itself.)
OR (3) Sneeze the word HNOF! (HNOF is the first four elements (hydrogen, nitrogen, oxygen and fluorine. Then, when you sneeze, your head goes down, which means the rest of the elements are below F!)
1) “7 that make a 7 and hydrogen” (Starting at element number 7, make a seven by going over 2 elements, and down 4 elements. Those you just went over are the diatomic element -- you’ll just have to remember hydrogen.)
OR (2) “GEN-u-INE” (If the element’s name ends in -gen or -ine, it is diatomic when by itself.)
OR (3) Sneeze the word HNOF! (HNOF is the first four elements (hydrogen, nitrogen, oxygen and fluorine. Then, when you sneeze, your head goes down, which means the rest of the elements are below F!)