who organized elements into four groups based on properties
History of the periodic table A number of physical elements (such as platinum, tin and zinc) have been known from antiquity, as they are found in their native form and are relatively simple to mine with primitive tools.[3] Around 330 BCE, the Greek philosopher Aristotle proposed that everything is made up of a mixture of one or more roots, an idea that had originally been suggested by the Sicilian philosopher Empedocles. The four roots, which were later renamed as elements by Plato, were earth, water, air and fire. Similar ideas about these four elements also existed in other ancient traditions, such as Indian philosophy. While Aristotle and Plato understood the concept of an element, their ideas did nothing to advance the understanding of the nature of matter.
Period 4 element A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the 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 fourth period contains 18 elements, beginning with potassium and ending with krypton. As a rule, period 4 elements fill their 4s shells first, then their 3d and 4p shells, in that order; however, there are exceptions, such as chromium.