  A modification of the standard periodic table of the elements reveals
$4n^{2}$ periods, where $n=2,3,\dots$. The new arrangement places hydrogen with
halogens and keeps the rare-earth elements in the table proper (without
separating them as they are in the standard table). Effectively, periods in the
modified table are defined by the halogens rather than by the noble gases. The
graph of ionization energy of the elements is presented for comparison of
periods in the standard and the modified tables.
