The boron group includes those elements in Group 13 (IIIa). Also the second group, the alkaline-earth metals, is considered to include beryllium, magnesium, calcium, strontium, barium, and radium but not the elements of Group 12 (IIb). The first group, the alkali metals, thereby includes, in addition to lithium and sodium, the metals from potassium down the table to francium but not the much less similar metals of Group 11 (Ib copper, etc.). The 17 elements of the fourth period, from potassium, 19, to bromine, 35, are distinct in their properties and are considered to constitute Groups 1–17 (Ia–VIIa) of the periodic system. The seven elements lithium to fluorine and the seven corresponding elements sodium to chlorine are placed in the seven groups, 1 (Ia), 2 (IIa), 13 (IIIa), 14 (IVa), 15 (Va), 16 (VIa), and 17 (VIIa), respectively.
#LITHIUM PERIODIC TABLE SERIES#
It is customary to refer to horizontal series of elements in the table as periods and vertical series as groups. The six noble gases-helium, neon, argon, krypton, xenon, and radon-occur at the ends of the six completed periods and constitute the Group 18 (0) group of the periodic system. Groups Classification of elements into groups The second very long period, from francium, 87, to oganesson, 118, is likewise condensed into 18 columns by the omission of the actinoids. The first very long period of 32 elements, from cesium, 55, to radon, 86, is condensed into 18 columns by the omission of the lanthanoids (which are indicated separately below), permitting the remaining 18 elements, which are closely similar in their properties to corresponding elements of the first and second long periods, to be placed directly below these elements. There follow two periods of 18 elements each: the first long period, from potassium 19, to krypton, 36 and the second long period, from rubidium, 37, to xenon, 54. Then there are two periods of eight elements each: the first short period, from lithium, 3, to neon, 10 and the second short period, from sodium, 11, to argon, 18. First there is the hydrogen period, consisting of the two elements hydrogen, 1, and helium, 2. The periodic table of the elements contains all of the chemical elements that have been discovered or made they are arranged, in the order of their atomic numbers, in seven horizontal periods, with the lanthanoids (lanthanum, 57, to lutetium, 71) and the actinoids (actinium, 89, to lawrencium, 103) indicated separately below. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.
#LITHIUM PERIODIC TABLE HOW TO#