I'm assuming you ask about the situation when isotopes has the same atomic number but different masses; this is normal because the number of neutrons in the isotopes of the same element is variable. But the number of protons (identical to atomic number) remain constant.
The atomic number of the isotopes of an element is identical; the mass number is different.
Not the atomic mass but the mass number (of course, these values are similar - not identical).The mass number is the sum between the number of protons and the number of neutrons. As a consequence:Number of neutrons for an isotope = Mass number - Number of protonsThe number of protons is equal to the atomic number.
No it is not the atomic number. We call it mass number.
We can find atomic mass and mass number in chemical elements. Atomic mass is about weight of the atom. Mass number is about total of neutrons and protons.
The main reason that the Atomic Mass of elements is not a whole number is due to the presence of different isotopes - these have the same number of protons in the nucleus but a different number of neutrons - so their masses are different even though chemically they are identical. The two isotopes of Chlorine are 35Cl- (75.77%) and 37Cl (24.23%) giving an overall "average" mass of 35.4527.
Those are different facts. atomic number is total of protons and neutrons.
isobars are elements with same mass numbers (Atomic Mass) and different atomic number (number of proton or electron)
atomic mass is the number of protons in an atom mass number is the number of protons plus neutrons in an atom
Isotopes : a different number of neutrons. The chemistry is almost identical (mainly the reaction times are slightly different.
mass number = number of protons + number of neutrons DIFFERENT FROM ATOMIC MASS atomic mass = weighted average of all the isotopes of that element
The atomic mass is an average, allowing for the relative abundances of different isotopes.
Number of neutrons = Atomic mass - Atomic number Atomic number of neon: 10 Atomic mass: depending on the neon isotope, each isotope has a different mass