APA stands for American Psychological Association. APA is often called name-and-date style. APA Format is widely used in psychology, business, education, engineering and the social sciences.The latest APA manual is called: Publication Manual of the American Psychological Association, sixth edition.
The elements are arranged in order of their increasing atomic number. Also the columns or groups are arranged by the number of valence electrons that a element has. For example, all the elements in column 1 have 1 valence electron meaning it has 1 electron in its outer shell. Elements in the same column tend to have similar if not identical properties.
Well usually elements in a periodic table are arranged into groups based on a set of repeating properties. However, Mendeleev arranged the elements in his periodic table in â¦ order of increasing atomic mass. Mendeleev arranged the elements in the increasing order of atomic masses and repeating periodic properties.They were arranged by the element's atomic mass. (lowest to highest) He arranged the elements in the increasing order of their atomic masses and repeating periodic properties.+ 31 others found this useful.mitri Mendeleev discovered scandium, gallium, technetium, and  germanium. He also predicted the existence of more elements and  developed the modern periodic table.