Determine the energy associated with an e- in hydrogen at n=2 to n=4

Kinetic energy of electron = -E₂ = 3.4 ev

Kinetic energy of electron = -E₄ = 0.85 ev

Explanation:

In case of hydrogen atom energy associated with nth state is,

En =  -13.6/n²

For n = 2

E₂ = -13.6 / 2²

E₂ = -13.6/4

E₂ = -3.4 ev

Kinetic energy of electron = -E₂ = 3.4 ev

For n = 4

E₄ = -13.6 / 4²

E₄ = -13.6/16

E₄ = -0.85 ev

Kinetic energy of electron = -E₄ = 0.85 ev

answer; /// the amount of material dissolved in a measure of liquid(concentration) the above statement is (true); /// good luck

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.