How are elements classified organized?

Theoretically, which metal should be the most reactive? hydrogen lithium francium fluorine

When a comet collides with earth, it adds material to our planet and causes great damage. therefore, a collision like this is a a. destructive force b. constructive force c. geologic process and event d. constructive and destructive force

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.