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:
- Hydrogen (H)
Hydrogen is in Group 1 (IA) of the periodic table, but it only has one electron in its outermost shell (valence shell). In contrast, the other Group 1 elements such as lithium (Li), sodium (Na), potassium (K), and so on, have one electron in their outermost shell as well.
The element that does not have the same number of electrons in its outermost shell as the other elements in its group is Copper (Cu).
In the periodic table, Copper belongs to Group 11, also known as the Coinage Metals or Group IB. The elements in this group traditionally have one electron in their outermost shell. However, Copper has a unique electron configuration where it has a partially filled 3d subshell instead of a filled 4s subshell. As a result, Copper has two electrons in its outermost shell rather than one, making it an exception in its group.