Which element does not have the same number of electrons in its outermost shell as the other elements in its group?
The element that does not have the same number of electrons in its outermost shell as the other elements in its group is helium (He).
In Group 18 of the periodic table, also known as the noble gases, all elements have a full outermost shell except for helium. Helium only has 2 electrons in its outermost shell, while the other elements in Group 18 have 8 electrons in their outermost shell.
The element that does not have the same number of electrons in its outermost shell as the other elements in its group is known as an exception or anomaly. There are a few examples of such elements:
1. Helium (He): In the noble gases group (Group 18), helium only has 2 electrons in its outermost shell, while the other elements in this group have 8 electrons.
2. Hydrogen (H): Although hydrogen is not technically grouped with any other elements, it is usually placed above Group 1. It has only 1 electron in its outermost shell, while the other elements in this group have 1 electron as well.
These are the two main exceptions in terms of electron configuration in their respective groups.