6.2. Electron Configuration and the Periodic Table http://www.ck12.org
FIGURE 6.9
A block diagram of the periodic table shows which sublevels are being filled at any point.
FIGURE 6.10
Like all alkali metals, sodium is very soft.
A fresh surface, which can be exposed by
cutting the sample, exhibits a luster that is
quickly lost as the sodium reacts with air.