91Ó°ÊÓ

Francium (Fr) is the last known alkali metal in the periodic table. It has an atomic number of 87. According to the periodic table, its ground-state electron configuration is [Rn]7s^1.

Alkali metals are located in group 1 of the periodic table. As we move down a group, the atomic number increases. The alkali metal after francium would be found in the next period, so its atomic number would be 87 + 1 = 88. However, element 88 (Radium) is not an alkali metal but an alkaline earth metal, located in group 2. To determine the correct position of the next alkali metal, we need to understand that a new period begins after the noble gas, so we need to move forward in the periodic table, after Radium (88) and Radon (86), the noble gas. Thus, the next alkali metal will be element 89 + 1 = 90.

The next alkali metal after francium has an atomic number of 90. Using the periodic table, we would predict that the ground-state electron configuration of this alkali metal would follow that of radon, the noble gas before it. Therefore, the electron configuration of this hypothetical alkali metal would be [Rn]6d^1. It is important to note that the actual element with an atomic number of 90 is thorium, which is not an alkali metal but an actinide. The next alkali metal in the periodic table is not yet discovered, and this prediction is based on periodic trends and electron configurations. In conclusion, the atomic number of the next alkali metal after francium is predicted to be 90, with a hypothetical ground-state electron configuration of [Rn]6d^1.