As we go across the rows of the periodic table, the overall shape of the table outlines how the electrons are occupying the shells and subshells.

Figure 8.15 The 3 d Subshell The 3d subshell is filled in themiddle section of the periodic table.Īnd so forth. This explains the section of 10 elements in the middle of the periodic table (Figure 8.15 “The 3d Subshell”). This is reflected in the structure of the periodic table.Īfter the 4s subshell is filled, the 3 d subshell is filled with up to 10 electrons. Figure 8.14 The 4s Subshell The 4s subshell is filled before the 3d subshell. Instead of filling the 3 d subshell next, electrons go into the 4 s subshell (Figure 8.14 “The 4s Subshell”). Figure 8.13 The 3p Subshell Next, the 3p subshell is filled with electrons. Next, the 3 p subshell is filled with the next six elements (Figure 8.13 “The 3p Subshell”). Figure 8.12 The 3s Subshell Now the 3s subshell is being occupied. The elements when this subshell is being filled, Na and Mg, are back on the left side of the periodic table (Figure 8.12 “The 3s Subshell”). The next subshell to be filled is the 3 s subshell. Figure 8.11 The 2p Subshell For B through Ne, the 2p subshell is being occupied. On the right side of the periodic table, these six elements (B through Ne) are grouped together (Figure 8.11 “The 2p Subshell”). Figure 8.10 The 2s Subshell In Li and Be, the 2s subshell is being filled.įor the next six elements, the 2 p subshell is being occupied with electrons. Figure 8.10 “The 2s Subshell” shows that these two elements are adjacent on the periodic table. The next two electrons, for Li and Be, would go into the 2 s subshell. Figure 8.10 “The 2s Subshell” shows that these two elements are adjacent on theperiodic table. Figure 8.9 The 1s Subshell The next two electrons, for Li and Be, would go into the 2s subshell. These two elements make up the first row of the periodic table (see Figure 8.9 “The 1s Subshell”). Their electron configurations are 1 s 1 and 1 s 2, respectively with He, the n = 1 shell is filled. Why does the periodic table have the structure it does? The answer is rather simple, if you understand electron configurations: the shape of the periodic table mimics the filling of the subshells with electrons. The elements are listed by atomic number (the number of protons in the nucleus), and elements with similar chemical properties are grouped together in columns. Determine the expected electron configuration of an element by its place on the periodic table.Ī periodic table is shown in Figure 8.8 “The Periodic Table”.Relate the electron configurations of the elements to the shape of the periodic table.

Valence electrons on the periodic table