Final answer:
The 3s orbital of a hydrogen atom has one radial node, which is a spherical shell around the nucleus where the electron probability density is zero.
Step-by-step explanation:
The question asks to locate the radial nodes in the 3s orbital of a hydrogen atom. A radial node is where the probability density of finding an electron in a particular orbital is zero. The number of radial nodes in an orbital can be determined using the formula n − 1 − ℓ, where n is the principal quantum number. For the 3s orbital of hydrogen, n is 3, so it has 3 − 1 − 1 = 1 radial node. This means there is one spherical shell around the nucleus where the probability of finding an electron is zero.