## kaylala Group Title Why do all atoms of an element have the same atomic number, although they may have different mass numbers? What do we call atoms of the same element with different mass numbers? ALSO SEE THE QUESTION other IN THE COMMENT AREA: one year ago one year ago

1. kaylala Group Title

OTHER QUESTION: Explain the meaning of each term in the symbol $\left(\begin{matrix}A \\ Z\end{matrix}\right) X$

2. thomaster Group Title

$$\Large\begin{matrix}A \\ Z\end{matrix} X$$ A= mass number (number of protons + neutrons) Z= atomic number (number of protons and number of electrons (when atom has a neutral charge) X= the element Atoms can have different mass numbers, these are called isotopes. Isotopes of an element have the same atomic number of the element because they have the same number of protons. The only difference is that isotopes have a different number of neutrons, that's why the mass number only changes.

3. kaylala Group Title

ok. thanks for your help @thomaster

4. UnkleRhaukus Group Title

The atomic number is equal to the number of protons, and thus also equal to the number of electrons that are stable in that element. The chemical properties of a element is due to the behaviour of the electrons. The number of neutrons wont effect the chemical behaviour because neutrons have no electronic charge.