a. the orbital is defined by n,L, mL so (n, L, mL, -1), (n, L,mL, 0) and (n,L,mL, +1) and 3 electrons for any given orbital 
b. in (n,L,mL,ms) format the first 12 elements would look like this 
 (1, 0, 0, +1) 
 (1, 0, 0, 0) 
 (1, 0, 0, -1) 
 (2, 0, 0, +1) 
 (2, 0, 0, 0) 
 (2, 0, 0, -1) 
 (2, 1, 0, +1) 
 (2, 1, 1, +1)<-----ANSWER
 (2, 1, 0, 0) 
 (2, 1, 1, 0) 
 (2, 1, 0, -1) 
 (2, 1, 1, -1) 
 the idea is we don't pair up electrons until all the mL's have 1 so we wouldn't write 
 (2, 1, 0, +1) 
 (2, 1, 0, 0) 
 (2, 1, 0, -1) 
 then. 
 (2, 1, 1, +1) 
 (2, 1, 1, 0) 
 (2, 1, 1, -1) 
 because they would fill 
 (2, 1, 0, +1)1st 
 (2, 1, 0, 0)3rd 
 (2, 1, 0, -1)5th 
 then. 
 (2, 1, 1, +1)2nd 
 (2, 1, 1, 0)4th 
 (2, 1, 1, -1)6th 
 to pair (or rather triple up) electrons last 
c. ideal gases are when each n level is full... 
 (1, 0, 0, +1) 
 (1, 0, 0, 0) 
 (1, 0, 0, -1)<----- ideal gas 3 electrons so 3 protons and atomic # = 3 
 (2, 0, 0, +1) 
 (2, 0, 0, 0) 
 (2, 0, 0, -1) 
 (2, 1, 0, +1) 
 (2, 1, 1, +1) 
 (2, 1, 0, 0) 
 (2, 1, 1, 0) 
 (2, 1, 0, -1) 
 (2, 1, 1, -1)<----- 2nd ideal gas12 e's so 12 p's and atomic # = 12 
 continuing on 
 (3, 0, 0, +1) 
 (3, 0, 0, 0) 
 (3, 0, 0, -1) 
 (3, 1, 0, +1) 
 (3, 1, 1, +1) 
 (3, 1, 0, 0) 
 (3, 1, 1, 0) 
 (3, 1, 0, -1) 
 (3, 1, 1, -1).. 
 (3, 2, 0, +1) 
 (3, 2, 1, +1) 
 (3, 2, 2, +1) 
 (3, 2, 0, 0) 
 (3, 2, 1, 0) 
 (3, 2, 2, 0) 
 (3, 2, 0, -1) 
 (3, 2, 1, -1) 
 (3, 2, 2, -1)<--- 3rd nobel gas atomic # = 30 
hope it helps