Final answer:
In Chemistry, for an atom with n=3, the possible subshells are 3s, 3p, and 3d, with a maximum of 18 electrons that can reside within these subshells. The 2s subshell can hold 2 electrons. Designations such as '1p' and '6d2-y' are incorrect.
Step-by-step explanation:
The question posed relates to the quantum numbers and the electronic configuration of atoms, which falls under the subject of Chemistry - specifically, the area dealing with atomic structure and electron arrangements. When addressing the part of the question that refers to n = 3, we consider the quantum numbers and permissible subshells for electrons within an atom.
For an atom with a principal quantum number (n) of 3, the possible values for the orbital angular momentum quantum number (l) can be 0, 1, or 2. This corresponds to the 3s, 3p, and 3d subshells, respectively. Utilizing the formula maximum number of electrons in a subshell = 2(2l + 1), we find that a maximum of 2 electrons can be in the 3s subshell (l=0), 6 electrons in the 3p subshell (l=1), and 10 electrons in the 3d subshell (l=2) for a total of 18 electrons that can have n = 3.
Additionally, there are 2 electrons in a 2s subshell because the maximum number of electrons in any s subshell is always 2. Subshells such as '1p' and '6d2-y' do not conform to the rules of quantum mechanics and do not exist; the 'py' notation does not accurately describe an orbital, and the 7py and 6d2-y designations are incorrect. The format should be 'px', 'py', or 'pz' for p-orbitals when specifying orientations, and there is no d subshell associated with the first (n=1) energy level, nor a 6d subshell notation paired with additional terms like '2-y'.