Gold and water are made up of identical units but gold is an element while water is not, do you know what makes gold an element but not water?
What is an Element?
Gold is made up of identical atoms which has only 79 protons, whereas water has two types of atoms in it, hydrogen with 1 proton and oxygen with 8 protons.
Although both are made up of identical units, atoms in case of gold and molecules in case of water, gold is an element but water is not its called compound. So, Elements are pure substance, pure because they are made up of only one type of atoms.
Hence if anything is made up of similar atoms is called an element and the one made from two or more simple elements are called compounds. We can distinguish one element from others by observing the number of protons in their individual atoms.
If there is one proton, its hydrogen; if there are two protons, it’s helium and so on. Wait! This means an increase in the number of protons can make new elements, then are there an infinite number of elements?
How Many Elements are There?
There are only 94 naturally occurring elements while there are 24 artificially synthesized elements. These 94 elements have built the entire matter universe known to us. Why just 94? Why elements cannot have more number of protons?
There is something that limits the number of protons in an atom. Protons are all situated in the central part, the nucleus of an atom. They also have positive charge and similar charges repel each other.
This electrostatic repulsion is very large for such short distance, trillionth fraction of a millimetre, which is nuclear diameter. So we have chargeless neutrons in the nucleus and they are bound together by very large force called strong force.
As the number of proton goes on increasing, the energy required to hold them together is very large. So, there cannot be a large number of protons in a single nucleus. Naturally, this number is 94.
Also, these atoms with a large number of protons in their nucleus like 88, 89, 90 and so on are not stable. They decay into atoms with lesser number of protons as the time goes by. The most stable element is iron with 26 protons in its atom.