Which of the following is NOT something the periodic table helps scientists do?

• A. Predict the chemical properties of elements
• B. Identify trends such as electronegativity and atomic radius
• C. Determine the atomic number of elements
• D. Calculate the exact mass of an atom's nucleus

Answer: (D)

Verified step by step guidance

1. Understand the primary purposes of the periodic table: it organizes elements based on their atomic number and electron configuration, which helps predict chemical properties and identify periodic trends.
2. Recognize that the periodic table provides the atomic number of each element, which is the number of protons in the nucleus and is fundamental to element identification.
3. Know that trends such as electronegativity, atomic radius, ionization energy, and electron affinity can be observed and predicted by examining the position of elements in the periodic table.
4. Realize that the periodic table does NOT provide information to calculate the exact mass of an atom's nucleus, as this requires knowledge of the number of protons and neutrons and their individual masses, which is beyond the scope of the periodic table itself.
5. Conclude that the option 'Calculate the exact mass of an atom's nucleus' is NOT something the periodic table helps scientists do, making it the correct answer.