As in DNA replication, RNA is synthesized in the 5' â 3' direction (from the point of view of the growing RNA transcript). Only one of the two DNA strands is transcribed. This strand is called the template strand, because it provides the template for ordering the sequence of nucleotides in an RNA transcript.
The properties of the chemical elements are summarized on the periodic table, which organizes the elements by increasing atomic number into rows (periods) in which the columns (groups) share recurring (periodic) physical and chemical properties.
Groups are the columns of the table. Atoms of elements within a group have the same number of valence electrons. These elements share many similar properties and tend to act the same way as each other in chemical reactions. The rows in the periodic table are called periods. Atoms of these elements all share the same highest electron energy level.