do periods in the periodic table have similar properties
A period in the periodic table is one of the horizontal rows, all of those elements have the same number of electron shells. Going across a period, each element has one more proton and is less metallic than its predecessor. Arranged this way, groups of elements in the same column have similar chemical and physical properties, reflecting the periodic law. For example, the alkali metals lie in the first column (group 1) and share similar properties, such as high reactivity and the tendency to lose one electron to arrive at a noble-gas electronic configuration. As of 2016 a total of 118 elements have been discovered and confirmed.
Period (periodic table)