Editing Period 5 element (section)

{{Short description|Fifth row of the periodic table}}
{{Periodic table (micro)| title=Period 5 in the [[periodic table]] | mark=Rb,Sr,Y,Zr,Nb,Mo,Tc,Ru,Rh,Pd,Ag,Cd,In,Sn,Sb,Te,I,Xe}}
{{Sidebar periodic table|expanded=structure }}
A '''period 5 element''' is one of the [[chemical element]]s in the fifth row (or [[Period (periodic table)|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 behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fifth period contains 18 elements, beginning with [[rubidium]] and ending with [[xenon]]. As a rule, period 5 elements fill their 5s [[electron shell|shells]] first, then their 4d, and 5p shells, in that order; however, there are exceptions, such as [[rhodium]].