Atomic Number of Caesium. Cesium or caesium is a metal with the element symbol Cs and atomic number 55. Melting point of Caesium is 28,4 °C and its the boiling point is 690 °C. Atomic Number of Caesium is 55.. Chemical symbol for Caesium is Cs. Caesium (IUPAC spelling) (also spelled cesium in American English) is a chemical element with the symbol Cs and atomic number 55. If the formula used in calculating molar mass is the molecular formula, the formula weight computed is the molecular weight. This is approximately the sum of the number of protons and neutrons in the nucleus. Relative atomic mass The mass of an atom relative to that of carbon-12. Calculate the fraction of the volume occupied by the nucleus in a cesium atom. This presents a particular hazard when radioactive cesium-137 contaminates the soil, as it did near Chernobyl.Growing plants require large amounts of potassium, and concentrate it from the soil. The mass number of the stable form of cesium is 133. The mass of a cesium (Cs, atomic number 55) atom is 2.21×10−25 kg, and its radius is R = 2.65×10−10 m. The mass of the atomic nucleus roughly equals the mass of the whole atom. This chemical element is distinctive for several reasons. Mass Percent: Cesium: Cs: 132.90545: 1: 100.000% ... of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all of these products together. How many electrons does cesium-137 have? It is a soft, silvery-golden alkali metal with a melting point of 28.5 °C (83.3 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. The compounds of cesium are similar to those of potassium. Atomic weight of Caesium is 132.905452 u or g/mol. Number of protons in Caesium is 55. Round your answer to 1 (one) significant figure. Caesium has physical and chemical properties similar to those of rubidium and potassium. Isotopes Cesium. The nuclear density is 2×1017 kg/m3. Density is the mass of a substance that would fill 1 cm 3 at room temperature. Where more than one isotope exists, the value given is the abundance weighted average. In atomic form (as opposed to being an ion), cesium-137 has 55 electrons, just as all cesium atoms have. Here is a collection of cesium …