Answers:
Atomic number = 63
Mass = 150.919 a.m.u
Nuclear symbol = ¹⁵¹Eu₆₃
Step-by-step explanation:
Europium (Eu) is a member of lanthanide series in periodic table. these are radioactive elements that emits radiations continuously. these elements are also called rare earth element due to their rare existent.
Europium (Eu) has two naturally occurring isotopes as follow,
1) Eu¹⁵² with 52.19 % abundance.
2) Eu¹⁵¹ with 47.81 % abundance.