What is the total number of orbitals in the third energy level (n=3)

Which one of the statements about electrons and atoms is now considered INCORRECT? Select one: a. Electrons are best described as standing waves oscillating in the space around the nucleus. b. Electrons have well-defined mass and charge, but their exact position is uncertain. c. Electrons circle the nucleus in elliptical orbits determined by the atom’s nuclear charge. d. In each energy level above n=1, there are multiple regions of space an electron can occupy. e. Two electrons can be paired in the same orbital as long as they have opposite spins.

Consider the electron configuration of the element Ni. How many unpaired electrons are there in the ground state electron configuration of Ni?   A. 4   B. 3   C. 0   D. 1   E. 2

Which set of quantum number is correct ? a. (1,1,0,+1/2) b. (1,2,1,+1/2) c. (1,0,1, -1/2) d. ( 1,0,0,0)