When Iodine solid is heated it changes directly to a gas; Which change of state is being observed?

Explanation:

When solid iodine is warmed, the solid sublimes and a vivid purple vapor forms. The reverse of sublimation is called deposition, a process in which gaseous substances condense directly into the solid state, bypassing the liquid state.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.