If you mean what group of elements react the most, the answer is the alkali metals and the halogens because they both only either need to gain or lose one electron. If you mean the most reactive element, it would be fluorine because it has the most electronegativity.
It is highly hazardous, it is radioactive
Answer: Most of them lie in a belt between Earth and Mars.
Explanation:
Asteroids are small rocky bodies having irregular shape size which orbit sun. Majority of the asteroids are found in a belt between orbits of Mars and Jupiter. Scientists presume that these asteroids are remains of a planet that never formed between Mars and Jupiter due to great gravitational pull of the largest planet of the solar -system - Jupiter.
Thus, the incorrect description of the asteroids is: Most of them lie in a belt between Earth and Mars.