What two-step process separated the cans into aluminum, steel, and tin?

Magnetivity and melting point.

Explanation:

Aluminum, steel and tin cans can be separated by two step process of magnetisation and melting point, because the three cans have different magnetic properties.

Steel attract to magnet easily because of it's has magnetic properties and these separate steel from aluminum.

Neither steel and aluminum melted at 300°C but Tin melt at that temperature.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.