Which of the following correctly describes elements in the same group on the periodic table?

• A. They have the same atomic number.
• B. They have the same number of electron shells.
• C. They have the same atomic mass.
• D. They have the same number of valence electrons.

Answer: (D)

Verified step by step guidance

1. Understand that the periodic table is organized into groups (columns) and periods (rows). Elements in the same group share certain chemical properties.
2. Recall that elements in the same group have the same number of valence electrons, which are the electrons in the outermost shell. This similarity in valence electrons results in similar chemical reactivity.
3. Note that elements in the same group do not have the same atomic number. The atomic number increases as you move down a group.
4. Recognize that elements in the same group do not have the same number of electron shells. The number of electron shells increases as you move down a group.
5. Understand that elements in the same group do not have the same atomic mass. Atomic mass generally increases as you move down a group due to the addition of more protons and neutrons.