Em tham khảo nha :
\(\begin{array}{l}
a)\\
Che:1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^1}\\
{Z_R} = 19\\
\Rightarrow R:Kali(K)\\
b)\\
Che:1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^{10}}4{s^1}\\
\Rightarrow R:Cu\\
C{u_2}O + 3{H_2}S{O_4} \to 2CuS{O_4} + S{O_2} + 3{H_2}O\\
5S{O_2} + 2{H_2}O + 2KMn{O_4} \to 2{H_2}S{O_4} + 2MnS{O_4} + {K_2}S{O_4}\\
{n_{S{O_2}}} = \dfrac{{0,56}}{{22,4}} = 0,025mol\\
{n_{C{u_2}O}} = {n_{S{O_2}}} = 0,025mol\\
{m_{C{u_2}O}} = 0,025 \times 144 = 3,6g\\
{n_{KMn{O_4}}} = \dfrac{2}{5}{n_{S{O_2}}} = 0,01mol\\
{C_{{M_{KMn{O_4}}}}} = \dfrac{{0,01}}{2} = 0,005M
\end{array}\)