Tumor markers are measurable biochemicals that are associated with a malignancy. They are either produced by tumor cells (tumor-derived) or by the body in response to tumor cells (tumor-associated). They are typically substances that are released into the circulation and thus measured in the blood.
â For example, the s subshell ( l = 0) contains only one orbital, and therefore the m l of an electron in an s subshell will always be 0. â The p subshell ( l = 1) contains three orbitals, so the m l of an electron in a p subshell will be -1, 0, or 1. â The d subshell ( l = 2) contains Â±ve orbitals, with m l values of -2, -1, 0, 1, and 2.
The 1 s subshell cannot hold 3 electrons (because an s subshell can hold a maximum of 2 electrons), so the electron configuration for a lithium atom cannot be 1 s. Two of the lithium electrons can fit into the 1 s subshell, but the third electron must go into the second shell.The second shell has two subshells, s and p, which fill with electrons in that order. The 2 s subshell holds a maximum of 2 electrons, and the 2 p subshell holds a maximum of 6 electrons.Because lithiumâs final electron goes into the 2 s subshell, we write the electron configuration of a lithium atom as 1 s 2 s.he 2 s subshell holds a maximum of 2 electrons, and the 2 p subshell holds a maximum of 6 electrons. Because lithiumâs final electron goes into the 2 s subshell, we write the electron configuration of a lithium atom as 1 s 2 s.