Isotopes.
The nucleus of an atom contains protons and neutrons. Different amount of neutrons- Isotopes. Different amount of protons- Different element.
Each element has a different number of protons and neutrons. So it changes for each element.
Isotopes are atoms of the same element, having the same number of protons but different number of neutrons.
Isotopes have the same amount of protons but a different amount of neutrons.
It is an isotope of the element.
Each chemical element has a different number of protons; the number of neutrons can be similar.
The isotopes of an element are alike in that they have the same number of protons, electrons, and the same chemical properties. The isotopes are different in that they have different numbers of neutrons and thus different atomic masses.
They have the same number of protons and different number of neutrons.
Atoms of the same element cannot have different numbers of protons. Different numbers of protons mean different elements. An atom with the a different number of neutrons is called an isotope.
Number of protons in in an element denote the type of element. So you identify element on the number of protons in it. Protons being positively charged can not sit together in a nucleus. They will repel each other. So you do not have an element in which only 2 or more protons and no neutrons are there.It means neutrons act as binding material in an element. So usually equal or more neutrons are there in an element. If same number of neutrons are there in nucleus but different number of protons, then it is no more a same but different element. An element in which different number of neutrons are there are called as Isotope. All element have got one or more Isotopes. So there 'physical' properties would differ but not 'chemical' property.
Not all atoms have an equal number of protons and neutrons. They can, but they don't have to. Helium, for example, has two of each, but carbon (always with 6 protons) can have 6, 7, or even 8 neutrons. The more neutrons, the more likely it is to be radioactive. The number of protons and neutrons gives the atomic weight of an atom. All of the various amounts of neutrons that an element can have are called isotopes of that element.
Each element has a unique number of protons. If another atom has the same number of protons as that element, it is the same element.