What is the electron configuration for Francium (Fr)?

Francium, with the atomic number 87, is an alkali metal located in Group 1 of the periodic table. To determine its electron configuration, it's essential to note how electrons are arranged in the different energy levels or shells surrounding the nucleus.

The electron configuration begins with the noble gas preceding francium in the periodic table, which is radon (Rn). Following radon, francium requires additional electrons to fill its configuration.

For francium, after the [Rn] core, it has one electron in the 7s orbital. Since it is in Group 1, it only contains one additional electron in the outermost shell, making the complete electron configuration [Rn] 7s^1. This reflects the fact that francium is the most reactive of the alkali metals and its single outer electron is characteristic of its reactivity.

In contrast, configurations that suggest two electrons in the 7s orbital or those involving 6d sublevels are not appropriate for francium's position and electron count according to its atomic number. Thus, the answer accurately represents the electron configuration for francium.