7. answer the following questions regarding a h atom in which an electron moves from the fourth energy level…

7. answer the following questions regarding a h atom in which an electron moves from the fourth energy level back to the second energy level. for both questions, express your answers to three significant figures.\n\na. calculate the energy change (in j) for the h atom. (7 pt)\nδe = (-2.178×10⁻¹⁸ j)(1/(2)² - 1/(4)²)\nδe = (-2.178×10⁻¹⁸ j)(1/4 - 1/16)\nδe = (-2.178×10⁻¹⁸ j)(0.1875)\nδe = -4.14×10⁻¹⁹ j 0.1875 3 s.f.\n\nb. what is the wavelength (in nm) of each photon of light emitted given this energy change? (11 pt)
Answer
Explanation:
Step1: Recall energy - wavelength formula
The energy - wavelength relationship is $E = h\nu=\frac{hc}{\lambda}$, where $E$ is energy, $h = 6.626\times10^{-34}\ J\cdot s$ (Planck's constant), $c= 2.998\times10^{8}\ m/s$ (speed of light), and $\lambda$ is wavelength. We know from part (a) that $E = 4.14\times 10^{-19}\ J$ (taking the magnitude since energy of the photon is positive).
Step2: Rearrange formula for wavelength
We can rearrange $E=\frac{hc}{\lambda}$ to $\lambda=\frac{hc}{E}$.
Step3: Substitute values
Substitute $h = 6.626\times10^{-34}\ J\cdot s$, $c = 2.998\times10^{8}\ m/s$, and $E = 4.14\times 10^{-19}\ J$ into the formula: [ \begin{align*} \lambda&=\frac{(6.626\times 10^{-34}\ J\cdot s)\times(2.998\times 10^{8}\ m/s)}{4.14\times 10^{-19}\ J}\ &=\frac{6.626\times2.998\times10^{-34 + 8}}{4.14\times 10^{-19}}\ m\ &=\frac{19.864748\times10^{-26}}{4.14\times 10^{-19}}\ m\ &=\frac{1.9864748\times 10^{-25}}{4.14\times 10^{-19}}\ m\ &= 4.80\times10^{-7}\ m \end{align*} ]
Step4: Convert to nanometers
Since $1\ nm=10^{-9}\ m$, then $\lambda=(4.80\times 10^{-7}\ m)\times\frac{1\ nm}{10^{-9}\ m}=480\ nm$.
Answer:
$480\ nm$