Which element has the smallest atomic number among the listed elements?

Which element has the smallest atomic number among the listed elements?

• A. Neon
• B. Sodium
• C. Boron
• D. Silicon

Answer: (C)

Atomic number equals the number of protons in an atom, which uniquely identifies an element. The elements listed have atomic numbers: boron has 5, neon has 10, sodium has 11, and silicon has 14. Since 5 is smaller than 10, 11, and 14, boron has the smallest atomic number. This reflects its position earlier in the periodic table compared to the others.

Atomic number equals the number of protons in an atom, which uniquely identifies an element. The elements listed have atomic numbers: boron has 5, neon has 10, sodium has 11, and silicon has 14. Since 5 is smaller than 10, 11, and 14, boron has the smallest atomic number. This reflects its position earlier in the periodic table compared to the others.