Which period includes the elements from potassium K through krypton Kr in the standard long-form table?
Q1. Which period includes the elements from potassium K through krypton Kr in the standard long-form table?
Answer: Period 4
Explanation: Period 4 begins with potassium (K, Z=19) and ends with krypton (Kr, Z=36), spanning 18 elements and including the first row of d-block transition metals.