Here's why:
* Atomic Size Trend: Atomic size generally increases as you move down a group (column) in the periodic table and decreases as you move across a period (row) from left to right.
* Placement:
* Lithium (Li) is in the first group (alkali metals), and the second period.
* Boron (B) is in the third group (boron group), and the second period.
* Carbon (C) is in the fourth group (carbon group), and the second period.
* Fluorine (F) is in the seventeenth group (halogens), and the second period.
Since Lithium is in the first group and the second period, it's located further to the left and lower than the other elements, making it the largest atom.
