The answer is: \(\boxed{\text{It is easier to remove an electron in a } p \text{ orbital than an } s \text{ orbital because it experiences less effective nuclear charge.}}\)
Group 15 elements have half-filled \(p\) orbitals, which are more stable due to electron pairing energy. Group 16 elements have one more electron, causing electron-electron repulsion, making it easier to remove an electron.
The answer is: \(\boxed{\text{Electron-electron repulsion in Group 16 makes it easier to remove an electron compared to Group 15.}}\)