Answer
Aluminum (Al): $ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^1 $
Gallium (Ga): $ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^1 $
Indium (In): $ 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^2 \, 4d^{10} \, 5p^1 $
Work Step by Step
aluminum (Al), gallium (Ga), and indium (In).
Let's determine the ground-state electron configurations for $ \bf Aluminum (Al)$:
The atomic number is 13.
Electron Configuration Process: The first 2 electrons fill the 1s orbital, the next 2 fill the 2s orbital, followed by 6 electrons in the 2p orbital, then 2 in the 3s orbital. The last electron goes into the 3p orbital.
Thus, the ground-state electron configuration of Al is
$$
\boxed{\;\;\text{Al}: 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^1\;\;}
$$
Let's determine the ground-state electron configurations for $ \bf Gallium (Ga)$:
The atomic number is 31.
Electron Configuration Process: The electrons fill the orbitals in the order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, and 4p. First, 2 electrons fill the 1s orbital, followed by 2 in the 2s, 6 in the 2p, 2 in the 3s, and 6 in the 3p. The 4s orbital then gets 2 electrons, followed by the 3d orbital with 10 electrons, and finally, 1 electron in the 4p orbital.
Thus, the ground-state electron configuration of Ga is
$$
\boxed{\;\; \text{Ga}: 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^1\;\;}
$$
Let's determine the ground-state electron configurations for $ \bf Indium (In)$:
The atomic number is 49.
Electron Configuration Process: The electrons fill the orbitals in the order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, and 5p. The first 2 electrons go into the 1s orbital, followed by 2 in the 2s, 6 in the 2p, 2 in the 3s, and 6 in the 3p. Then, 2 electrons fill the 4s orbital, followed by 10 electrons in the 3d, 6 in the 4p, 2 in the 5s, 10 in the 4d, and finally, 1 electron in the 5p orbital.
Thus, the ground-state electron configuration of In is
$$
\boxed{\;\; \text{In}: 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 4s^2 \, 3d^{10} \, 4p^6 \, 5s^2 \, 4d^{10} \, 5p^1\;\;}
$$
