Step 1: The Bohr model is applicable to hydrogen-like atoms, where there is a single electron in orbit around the nucleus. For other atoms with multiple electrons, the Bohr model fails to explain their behavior accurately.
Step 2: In the case of a doubly ionized helium atom, the atom has no electrons, making the Bohr model invalid for such systems. Therefore, the Bohr model does not work for the doubly ionized helium atom.
For the reaction:
\[ 2A + B \rightarrow 2C + D \]
The following kinetic data were obtained for three different experiments performed at the same temperature:
\[ \begin{array}{|c|c|c|c|} \hline \text{Experiment} & [A]_0 \, (\text{M}) & [B]_0 \, (\text{M}) & \text{Initial rate} \, (\text{M/s}) \\ \hline I & 0.10 & 0.10 & 0.10 \\ II & 0.20 & 0.10 & 0.40 \\ III & 0.20 & 0.20 & 0.40 \\ \hline \end{array} \]
The total order and order in [B] for the reaction are respectively: