The proton numbers and nucleon numbers of four nuclides are shown.
Which statement is correct?
Plutonium (Pu) contains one more proton than uranium (U).
Thorium (Th) contains one more neutron than radium (Ra).
Thorium (Th) contains one more proton than radium (Ra).
Uranium (U) contains one more neutron than plutonium (Pu).