What is thallium 201? Chemistry Matter Elements 1 Answer anor277 Jul 21, 2017 An isotope of thallium...........? Explanation: This site reports the isotopes of thallium, #Z=81#. There are thus #120# neutrons in the nucleus of #""^(201)Tl#. Do you agree? I am not a nuclear chemist, but this isotope is probably screaming hot........ Answer link Related questions What periodic table elements are radioactive? How can the periodic table be used to predict the properties of the elements? How can elements have different isotopes? How can elements be broken down? How can elements properties be predicted? What is a chemical element? What element in the fourth period of the periodic table has 5 valence electrons? How are chemical elements diffrent from chemical compounds? What does organic chemistry study? How do elements change from left to right in the periodic tabale? See all questions in Elements Impact of this question 2185 views around the world You can reuse this answer Creative Commons License