Editing Period 7 element (section)

{{Short description|Any element in row 7 of the periodic table}}
{{Periodic table (micro)| title=Period 7 in the [[periodic table]] | mark=Fr,Ra,Ac,Th,Pa,U,Np,Pu,Am,Cm,Bk,Cf,Es,Fm,Md,No,Lr,Rf,Db,Sg,Bh,Hs,Mt,Ds,Rg,Cn,Nh,Fl,Mc,Lv,Ts,Og}}
{{Sidebar periodic table|expanded=structure }}
A '''period 7 element''' is one of the [[chemical element]]s in the seventh row (or [[Periodic table period|period]]) of the [[periodic table|periodic table of the chemical elements]]. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases: a new row is begun when chemical behavior begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. The seventh period contains 32 elements, tied for the most with [[Period 6 element|period 6]], beginning with [[francium]] and ending with [[oganesson]], the heaviest element currently discovered. As a rule, period 7 elements fill their 7s [[electron shell|shells]] first, then their 5f, 6d, and 7p shells in that order, but there are exceptions, such as [[uranium]].