Kemija - 2025./26. jesen - 18.

${}_{10}^{21}\mathrm{N}\mathrm{e}\{\; \}\_\{10\}^\{21\}\; \backslash mathrm\{Ne\}$

${}_{11}^{22}\mathrm{N}\mathrm{a}\{\; \}\_\{11\}^\{22\}\; \backslash mathrm\{Na\}$

${}_8^{18}{\mathrm{O}}^{2-}\{\; \}\_\{8\}^\{18\}\; \backslash mathrm\{O\}^\{2-\}$

${}_{12}^{24}{\mathrm{M}\mathrm{g}}^{2+}\{\; \}\_\{12\}^\{24\}\; \backslash mathrm\{Mg\}^\{2+\}$