5 Steps to a 5 AP Chemistry 2019

(^50) › STEP 4. Review the Knowledge You Need to Score High
Table 5.2 Summary of Atomic Shell, Subshells, and Orbitals for Shells 1–4
SHELL (ENERGY LEVEL) SUBSHELL NUMBER OF ORBITALS ELECTRON CAPACITY
1 s 1 2 total
2 s 1 2
p 3 6
8 total
3 s 1 2
p 3 6
d 5 10
18 total
4 s 1 2
p 3 6
d 5 10
f 7 14
32 total
level 2 (shell 2) has two subshells. The subshells are denoted by the symbols s, p, d, f, etc.,
and correspond to differently shaped volumes of space in which the probability of finding
the electrons is high. The electrons in a particular subshell may be distributed among vol-
umes of space of equal energies called orbitals. There is one orbital for an s subshell, three
for a p, five for a d, seven for an f, etc. Only two electrons may occupy an orbital. Table 5.2
summarizes the shells, subshells, and orbitals in an atom. Chapter 10 on Spectroscopy,
Light, and Electrons has a discussion of the origin of this system.
Energy-Level Diagrams
The information above can be shown in graph form as an energy-level diagram, as shown
in Figure 5.1:
5p
4p
3p
2p
4d
3d
5s
4s
3s
2s
1s
Figure 5.1 Energy-level diagram of an atom.