Chemistry 4.1

John Newlands

noticed a periodic pattern; English chemist who arranged the known elements according to their properties and in order of atomic mass

law of octaves

Newlands arrangement of elements seemed to repeat every eight elements, so this was what his pattern was called

Dmitri Mendeleev

inventor of first periodic table; Russian chemist; arranged elements in order of increasing atomic mass and started a new row each time he noticed that the chemical properties of the elements repeated

periodic table

A chart of the elements showing the repeating pattern of their properties

Henry Moseley

English chemist; found a different physical basis for the arrangement of elements; found that spectral lines correlated to atomic number, not to atomic mass; showed that atomic number, not atomic mass, is the basis for the organization of the periodic table

periodic law

law that states that the repeating physical and chemical properties of elements change periodically with their atomic number; when elements are arranged according to their atomic numbers, elements with similar properties appear at regular intervals

valence electrons

an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties

group

a vertical column of elements in the periodic table; share chemical properties

metalloids

Elements that may accept or donate electrons readily and possess a mixture of metallic and nonmetallic properties

period

a horizontal row of elements in the periodic table; have the same number of occupied energy levels

minerals

Elements found in food that are used by the body; macronutrients

trace elements

micronutrients; An element indispensable for life but required in extremely minute amounts.