Silicon (Si) is located in period 3 of the periodic table. What does this indicate about silicon?

• A. It has three electron shells.
• B. It is a transition metal.
• C. It is found in group 3.
• D. It has three valence electrons.

Answer: (A)

Verified step by step guidance

1. Understand that the period number in the periodic table corresponds to the number of electron shells (energy levels) an element has. Since silicon is in period 3, it means silicon has 3 electron shells.
2. Recall that transition metals are found in the d-block of the periodic table, typically in groups 3 to 12. Silicon is not in this block, so it is not a transition metal.
3. Recognize that the group number indicates the number of valence electrons for main group elements. Silicon is in group 14, so it does not have 3 valence electrons.
4. Summarize that being in period 3 means silicon has three electron shells, which is the key information indicated by its period placement.
5. Therefore, the correct interpretation of silicon being in period 3 is that it has three electron shells.