Do all isotopes of an element have the same atomic number?

Question

Ellie Andrews · Accepted Answer

Yes, absolutely. Because, by definition, the element hydrogen is defined by #Z=1#, the atomic number, the number of positively charged particles in the atomic nucleus.

The element hydrogen is created when there is only one positively charged particle, or one proton, in the atomic nucleus; if there are two, helium; if there are twenty-three, vanadium, etc. The atomic number, #Z#, thus determines elemental identity; and this relates to the number of protons, positively charged nuclear particles, contained in the nucleus. Of course, there may be relatively different numbers of NEUTRAL particles (i.e. NEUTRONS) contained in the nucleus, which gives rise to the existence of isotopes. For the simplest atom, hydrogen, we would normally encounter #""^1H#, the protium nucleus. A smaller percentage of hydrogen atoms would have 1 neutron in the nucleus, to give deuterium, i.e. #""^2H#; an even smaller percentage has 2 neutrons in the nucleus to give the tritium isotope, #""^3H# These are basic and fundamental principles that should be understood. Don't be afraid to speak up if you have any questions or objections. The most significant piece of information is that elemental identity is determined by the atomic number! Keep in mind that you will ALWAYS be given a Periodic Table for every Chemistry exam you take, which will provide you with the average isotopic mass.

Owen Ambrose · Answer

All atoms of the same element have the same atomic number.

The number of protons in an element's nuclei is known as its atomic number. An element's atoms all have the same atomic number, but its isotopes—for example, hydrogen—have different numbers of neutrons in their nuclei but the same number of protons in their nuclei. There are three different isotopes of hydrogen: hydrogen-1, hydrogen-2, and hydrogen-3. The atomic number of hydrogen is 1. The nuclei of hydrogen-1, hydrogen-2, and hydrogen-3 atoms each contain one proton and zero neutrons, one proton and one neutron, and one proton and two neutrons, respectively. It is important to note that all hydrogen isotopes, regardless of the number of neutrons, have the same number of protons in their nuclei, and as a result, have the same atomic number, which is 1, as shown in the periodic table.

Cameron Andrews · Answer

Yes

An isotope of an element is just that same element but with a different number of neutrons, therefore different atomic mass. A normal hydrogen atom has a mass of #1 \ "u"#, and so is denoted by #""^1H#. Isotopes of hydrogen include deuterium and tritium, which are hydrogen-#2# and hydrogen-#3#, respectively. They are denoted by #""^2H# and #""^3H#. Note that they are still the same element, as the atomic (proton) number is responsible on what element is currently there. It doesn't matter if we somehow create #""^1000H#, it will still be hydrogen, and react the same way in a chemical reaction like normal hydrogen would.

Serenity Allen · Answer

undefined Indeed, an element's isotopes all have the same atomic number.