5 Steps to a 5 AP Chemistry

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

2s12

p3 6

8 total

3s12

p3 6

d5 10

18 total

4s12

p3 6

d5 10

f7 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. The chapter on Spectroscopy,

Light, and Electrons, Chapter 10 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:

48  STEP 4. Review the Knowledge You Need to Score High

5p

4p

3p

2p

4d

3d

5s

4s

3s

2s

1s

Figure 5.1 Energy-level diagram of an atom.