Answer:
The key difference between empirical and molecular formulas is that an empirical formula only gives the simplest ratio of atom whereas a molecular formula gives the exact number of each atom in a molecule.
If it is blue litmus paper, it will remain blue. If it is red litmus paper, it will remain red. Water is neither an acid nor a base so it will not change the litmus paper.
The outermost energy shell of an atom
because they are involved in forming bonds
A neutral atom of potassium has 19 electrons.