Which of the subshell to which the last electron was added?

Q. Which is the subshell of lithium to which the last electron was added?

Q. What about the subshell to which the last electron of nitrogen was added

Q. What is the relation between the subshell to which the last electron was added and the block to which the element belongs?

Q. Complete the Table

Element	Atomic number	Subshell electronic configuration	The subshell to which the last electron is added	Block
${}_{3}Li$	......	......	.......	......
${}_{12}Mg$	......	......	.......	.....
${}_{7}N$	......	........	.......	.......
${}_{21}Sc$	.....	.......	.....	.......

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Q. The three unpaired electrons in the last subshell of nitrogen are related to the following law: