In Choose Odd Word, There are four words in each group. One word in each group is different from the rest. You must choose which is the odd word. Which word does not match with the rest of the group?

Choose or find odd word

Radium , Thorium , Sodium , Polonium , Uranium

A. Radium
B. Thorium
C. Sodium
D. Polonium
E. Uranium
Answer: C . Sodium

Justification: All except Sodium are radio-isotopes, while sodium is a metal.