Which of the following properties are different for neutral atoms of isotopes of the same element?

Match the following species with their respective number of electrons:
| Species | Number of electrons |
| :--- | :--- |
| $(a)$ $O^{2-}$ | $(i)$ $18$ |
| $(b)$ $Li^{2+}$ | (ii) $2$ |
| $(c)$ $He$ | (iii) $10$ |
| $(d)$ $Ca^{2+}$ | (iv) $1$ |

An element has an electronic configuration of $2, 8, 18, 1$. If its atomic weight is $63$,then how many neutrons will be present in its nucleus?

What is the representation of an element having a mass number of $40$ and $21$ neutrons in it?

The number of protons,neutrons,and electrons in the element $_{89}X^{231}$ are respectively:

Match the isotopes in List $I$ with the number of neutrons in List $II$.

$(A)$. $^{24}_{12}Mg$	$(I)$. $5$
$(B)$. $^{27}_{13}Al$	$(II)$. $12$
$(C)$. $^{9}_{4}Be$	$(III)$. $6$
$(D)$. $^{12}_{6}C$	$(IV)$. $14$