Atomic structure 2 answer
How are the electrons arranged, in terms of 1s, 2p etc, in the following atoms and ions?
N (atomic number = 7) 1s22s22p3
Na (atomic number = 11) 1s22s22p63s1
Ca (atomic number = 20) 1s22s22p63s23p64s2
Fe (atomic number = 26) 1s22s22p63s23p64s23d6
Cu (atomic number = 29) 1s22s22p63s23p64s13d10
but 1s22s22p63s23p64s23d9 would be allowed.
Fe2+ (atomic number = 26) 1s22s22p63s23p63d6
(Two less electrons because of the 2+ charge. The order of filling goes back to the main shell numerical order and so the 4s electrrons are the highest energy ones and, consequently, they are the ones to leave.)
Also comment on any special features of the arrangement in N.
The three electrons in the 2p orbitals have to be in three different p orbitals (px, py, pz) ands must have parallel spin (either all upspin or all downspin, it doesn't matter which).