Name the elements that comprise the atoms of bond TR001_2_4.
element = 'cl' means Chlorine; element = 'c' means Carbon; element = 'h' means Hydrogen; element = 'o' means Oxygen, element = 's' means Sulfur; element = 'n' means Nitrogen, element = 'p' means Phosphorus, element = 'na' means Sodium, element = 'br' means Bromine, element = 'f' means Fluorine; element = 'i' means Iodine; element = 'sn' means Tin; element = 'pb' means Lead; element = 'te' means Tellurium; element = 'ca' means Calcium
SELECT DISTINCT T1.element FROM atom AS T1 INNER JOIN connected AS T2 ON T1.atom_id = T2.atom_id WHERE T2.bond_id = 'TR001_2_4'