Answer:
Step-by-step explanation:
Ground state electron configuration of potassium (K) is 1s2 2s2 2p6 3s2 3p6 4s1. The valency of the element is determined by electron configuration in the excited state. This electron configuration shows that the last shell of the potassium atom has an unpaired electron (4s1). So the valency of potassium is 1.