All the elements in period 3 have this characteristic

they all have 3 neutrons

they all have 3 protons

they all have 3 orbitals (shells)

they all have atomic masses that are a multiple of 3

(offering 98 points)

The answer would be C). All of the elements inside a period will always have the same amount of shells. Hope this helps!

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.