Find the weight on the Periodic Table then subtract the proton numbers.
Hydrogen is the only element without any neutrons.
There are 8 neutrons in oxygen. You can determine the number of neutrons in any element by subtracting the atomic number (which is 8 for oxygen) from the atomic mass, rounded to the nearest whole number (which is 16 for oxygen). This is because the mass of any element comes mainly from the protons and the neutrons - the mass of the electrons is too tiny to be a significant contribution. The atomic number corresponds to the number of protons in an element, so when you subtract it from the element's total mass, you are left with the number of neutrons.
its atomic numberthe number of neutrons
It is the neutron that makes changes in atomic nuclei to change them from one isotope to another. For any given element, that element will have a fixed number of protons. It is, after all, the number of protons that determine the elemental identity. But the number of neutrons in a given element can vary, and we use the term isotope to talk about which particular atom we're investigating. That is, we apply the term isotope to speak to an atom of a given element with a certain number of neutrons in its nucleus.
Neutrons are neutrally charged. It is not possible to determine the charge of an atom through knowledge of the number of neutrons contained within its nucleus. Consider hydrogen, for example. It has no neutrons, one proton, and one electron. Its charge is neutral. Deuterium is hydrogen with a neutron, but also has the same charge. Tritium is hydrogen with two neutrons within its nucleus--again, no charge.
If this were to happen, which for most nuclei would be unbelievably unlikely, it would form a different isotope of the same element. I can't offhand think of any way a nucleus could gain or lose a neutron without something else happening at the same time. A neutron can change into a proton by emitting an electron (and an electron antineutrino), or a proton can absorb an electron and change into a neutron, but in both of these cases there's more going on than just the neutron number of the nucleus changing.
The number of protons is equal to atomic number and the number of electrons (for a neutral atom).
The atomic number is equal to the number of protons in an atom's nucleus. To determine the atomic number of an element, you simply count the number of protons in the nucleus of an atom of that element. This number is unique for each element and is listed on the periodic table of elements.
The mass number is the sum of the number of neutrons and protons. If we already know that there is one neutron and the mass number is two, then that means there is one proton. Any atom with one proton is hydrogen. This particular isotope is called deuterium.
The only rule for any set is that given any element [number], you should be able to determine whether or not it is a member of the set.
No! Avogadro just guessed the average number of molecules,ions,atoms number in one mole of any compound,element,etc.
An atom of any element must contain protons, neutrons, and electrons. The number of protons in the nucleus determines the element's identity, while the neutrons and electrons help determine its stability and reactivity.