Question

Predict the atomic number of the next alkali metal after francium and give its ground-state electron configuration.

Short answer

The predicted atomic number of the next alkali metal after francium is 119. Assuming the current Aufbau principle applies, its ground-state electron configuration would be: \[ 1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^6 \ 7s^{1} \]

Step-by-step solution

Determine the atomic number for francium

Francium is the last known alkali metal in the periodic table. Its atomic number is 87.

Predict the atomic number of the next alkali metal

As alkali metals are in the first group of the periodic table and have one electron in their outermost energy level, we can predict the next alkali metal's atomic number by adding one full period (or row) of elements to 87. One full period contains 32 elements, so the next alkali metal's atomic number would be: 87 + 32 = 119 Thus, the predicted atomic number of the next alkali metal would be 119.

Determine the ground-state electron configuration

To give the ground-state electron configuration of the new element, we need to distribute the 119 electrons in the energy levels following the Aufbau principle. The expected order of filling of electrons is: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p However, as we are dealing with an unknown element with an atomic number larger than the current periodic table, we should take into account that the order of filling might not remain the same. The electron configuration for the new element might deviate from the Aufbau principle. Assuming the current Aufbau principle applies, the ground-state electron configuration for element 119 would be: \[1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^6 \ 7s^{1}\] The ground-state electron configuration for the predicted element with atomic number 119 is: \[1s^2 \ 2s^2 \ 2p^6 \ 3s^2 \ 3p^6 \ 4s^2 \ 3d^{10} \ 4p^6 \ 5s^2 \ 4d^{10} \ 5p^6 \ 6s^2 \ 4f^{14} \ 5d^{10} \ 6p^6 \ 7s^{1}\]