# The valence electron in potassium requires 6.95 xx 10^-19 "J" of energy to be removed. What frequency of light can do this? What type of electromagnetic radiation could do this?

Jul 3, 2017

Very blue visible photons or UV photons.

#### Explanation:

$K$ electron configuration: $\left[A r\right] 4 {s}^{1}$

This electron in the $4 s$ orbital requires $E = 6.95 \cdot {10}^{-} 19 J$ to be emitted. This is merely a question of the photon's energy being that which meets this requirement, thus,

$6.95 \cdot {10}^{-} 19 J = \left(6.626 \cdot {10}^{-} 34 J \cdot s\right) v$
$v = 1.05 \cdot {10}^{15} {s}^{-} 1$

Now, referring to the EMR diagram that I gaurantee you most people don't have absolutely memorized:

This energy corresponds with the frequency of very blue photons (visible) or UV photons.