203-- The outermost electronic configuration of the monoatomic ions $A^{r-}$, $D^{r+}$, and $E^{r+}$ ends in $3p^6$, $4p^6$, and $3d^5$ respectively. Which statement about them is correct?
Element E is in group 7 and element D is in group 13 of the periodic table.
The reactivity of elements E and D is greater than that of alkali metals in the same period.
The chemical properties of element A resemble those of its own period-18 group element.
The atomic number of one of the elements in the same group as element A, in the periodic table, is equal.
\textbf{203--} The outermost electronic configuration of the monoatomic ions $A^{r-}$, $D^{r+}$, and $E^{r+}$ ends in $3p^6$, $4p^6$, and $3d^5$ respectively. Which statement about them is correct?
\begin{enumerate}
\item Element E is in group 7 and element D is in group 13 of the periodic table.
\item The reactivity of elements E and D is greater than that of alkali metals in the same period.
\item The chemical properties of element A resemble those of its own period-18 group element.
\item The atomic number of one of the elements in the same group as element A, in the periodic table, is equal.
\end{enumerate}