Chapter 7 - Electronic Structure - Questions and Exercises - Exercises - Page 286: 7.41

2.3 nm

Wavelength, λ = $\frac{h}{mv}$ Planck's constant, h = $6.626\times10^{-34}Js$ Mass, m= $1.67\times10^{-27}kg$ Velocity, v = $1.7\times10^{2}$ m/s λ = $\frac{6.626\times10^{-34}Js}{1.67\times10^{-27}kg\times1.7\times10^{2}m/s}$ = $2.3\times10^{-9}m$ = 2.3 nm