Question

Which of the following is not radioactive?
A.Astatine
B.Francium
C.Tritium
D.Zirconium

Answer 1

Hint:Radioactivity is also known as nuclear decay or radioactive decay. In radioactivity, an unstable atomic nucleus loses energy by radiation. Three of the most common types of decay are alpha decay, beta decay and gamma decay. Mostly isotopes with high neutrons and elements of the 7th period are radioactive.

Complete step by step answer:
Astatine is a chemical element with the symbol At. Its atomic number is 85 and it is the rarest naturally occurring element in the earth’s crust. All of the astatine’s isotopes are short lived as it is radioactive. The half life of astatine is 8.1 hours.
Francium is a chemical element with the symbol Fr. Its atomic number is 87. Before it was discovered, it was called eka-caesium. It is extremely radioactive. Its most stable isotope has a half life of only 22 minute. Due to the instability of francium, it has no commercial applications. It is the second most electropositive element after caesium.
Tritium is a rare isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons. It is radioactive with half life of 12.32 years. The beta particles released by small amounts of tritium lead to a glow of phosphors. It is a vital component in nuclear weapons. It can also be used in beta voltaic devices to generate electricity.
Zirconium is an element with the symbol Zr and the atomic number of Zr is 40. It is a transition metal which is lustrous. It is mainly used as a refractory. It is not radioactive. Most zircon is utilized in high temperature applications.

Hence, Zirconium is not radioactive and the correct answer is D.
Note:
Radioactive decay is the spontaneous breakdown of an atomic nucleus resulting in the release of energy from the nucleus.Radioactive decay is a random process at the level of solitary atoms. It gives rise to phenomena like nuclear fusion or fission.