Potassium outermost electron occupy "4s" orbital
Your answer is going to be B. at the focal point of the lens. :)
Answer:

Explanation:
Here, we want to get the equation of the reaction between Hydrochloric acid and Zinc metal
Zinc metal displaces the hydrogen from hydrochloric acid to form zinc chloride
We have the equation of reaction as:
C) energy level
Looking at quantum mechanics, we see that electrons exist at certain energy levels. When they get excited, they’ll jump from one energy state to a higher energy state and down. We can the. Look at the color it admits and determine what the energy level is.
The answer to your question is radiation