Answer :

To determine which of the given elements—Li (Lithium), O (Oxygen), C (Carbon), and F (Fluorine)—has the smallest atomic radius, we need to compare their atomic radii.

Here are the atomic radii of each element:
- Lithium (Li) has an atomic radius of 152 picometers.
- Oxygen (O) has an atomic radius of 60 picometers.
- Carbon (C) has an atomic radius of 70 picometers.
- Fluorine (F) has an atomic radius of 50 picometers.

Now we compare these values:

1. Lithium: 152 picometers
2. Oxygen: 60 picometers
3. Carbon: 70 picometers
4. Fluorine: 50 picometers

Among these values, the smallest atomic radius is 50 picometers.

Therefore, the element with the smallest atomic radius is Fluorine (F).
So, the element with the smallest atomic radius is F (Fluorine).