Question

according to the aufbau procedure for neutral atoms:
which subshell is filled immediately before the 6d subshell? (enter 1s, 2s, 2p, etc. as appropriate.)
which subshell fills immediately after the 6d subshell? (enter 1s, 2s, 2p, etc. as appropriate.)

Explanation:

Step1: Recall the Aufbau principle

The Aufbau principle states that electrons fill orbitals in order of increasing energy. The order of filling is given by the \(n + l\) rule. For a given subshell with principal quantum number \(n\) and azimuthal quantum number \(l\), the energy is approximately proportional to \(n + l\). If two subshells have the same \(n + l\) value, the one with lower \(n\) is filled first.

Step2: Determine the subshell before \(6d\)

For the \(6d\) subshell, \(n = 6\) and \(l=2\), so \(n + l=6 + 2=8\).
Let's consider the subshells with \(n + l = 8\). The \(5f\) subshell has \(n = 5\) and \(l = 3\), so \(n + l=5+3 = 8\). But we also need to check the order. The order of filling for \(n + l = 8\) is \(5f\), \(6d\). Wait, no. Let's use the Aufbau order: \(1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p\)

The subshell before \(6d\) is \(5f\).

Step3: Determine the subshell after \(6d\)

After \(6d\), using the Aufbau order \(1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p\), the subshell after \(6d\) is \(7p\)

Answer:

Before \(6d\): \(5f\)
After \(6d\): \(7p\)