Which property can be determined from the period in which an element appears on the periodic table?

• A. The number of electron shells in the atom
• B. The typical ionic charge of the element
• C. The atomic mass of the element
• D. The number of valence electrons

Answer: (A)

Verified step by step guidance

1. Understand that the periodic table is arranged in periods (horizontal rows) and groups (vertical columns). Each period corresponds to the filling of a specific electron shell in the atom.
2. Recall that the period number indicates the highest principal energy level (or electron shell) that contains electrons for the elements in that period.
3. Recognize that the number of electron shells in an atom increases as you move down the periods in the periodic table.
4. Note that properties like ionic charge and number of valence electrons are more closely related to the group (column) rather than the period.
5. Conclude that the property determined by the period number is the number of electron shells in the atom.