<span>We have ground strate configurations of electrons,if electrons are filled in order of increasing energy. When there are electrons are in higher orbitals, we have an atom in an excited state.
B, and C are excited states.
In B, 2 electrons can fit in the 4s orbital, and that should fill fully before the 4p orbitals.
In C, the same is true for 5s and 5p
In D, this is not an excited state because 4s fills before 3d</span>
To convert the mass of a compound to formula units, the conversion factor is Avogadro's number, 6.022 x10^23 formula units/ mol and its molar mass. In this case, we are given with 19.0 grams of magnesium chloride which has a mass of 95.21 g/mol. Hence the answer is 1.20 x 10^23 formula units.
An element cannot be broken down into any other substance by physical or chemical means.
10 atoms. If there are 10 in the reactants you need the same number in the products
