Which of the following elements have the same number of valence electrons? I. Nitrogen (N)
II. Oxygen (O)
III. Fluorine (F)
IV. Sulfur (S)
V. Selenium (Se)

The answer is II. Oxygen, IV. Sulfur, and V. Selenium.

Explanation:

Going down the list that was provided, we can use the periodic table of elements to determine the valence electrons.

- Nitrogen has 5 valence electrons
- Oxygen has 6 valence electrons
- Fluorine has 7 valence electrons
- Sulfur has 6 valence electrons
- Selenium has 6 valence electrons

Since oxygen, sulfur, and selenium all have 6 valence electrons, then that is the correct answer.