133 is the answer, because the atomic number is the number of protons in an atom, and the mass is the number of protons plus the number of … The Element Cesium Atomic Number: 55 Atomic Mass: 132.91 Melting Point: 301.59 K (28.44°C or 83.19°F) Boiling Point: 944 K (671°C or Cesium (Cs) is a chemical element in the periodic table with atomic number 55 discovered by Fustov Kirchhoff and Robert Bunsen in the year 1860. Caesium or cesium is a chemical element with symbol Cs and atomic number 55. the atomic number of cesium (Cs) is 55. Explanation: New questions in Physics. Relative atomic mass The mass of an atom relative to that of carbon-12. Cesium is a chemical element with symbol Cs and atomic number 55. CAS number If an atom of cesium has 78 neutrons, what is the atomic mass of cesium? Answers (1) Sebella 7 August, 05:52. This name has been derived from a Latin word Caesius which means sky blue, as it ignites with blue fire. This is approximately the sum of the number of protons and neutrons in the nucleus. If an atom of cesium has 78 neutrons, what is the atomic mass of cesium? Cesium formate-based drilling fluids are extensively used in extractive oil industry. Cesium (Cs) is a compound element with atomic number 55 in the periodic table found by Gustov Kirchhoff and Robert Bunsen in the year 1860. Uses of Cesium. The atomic number of cesium (Cs) is 55.The atomic weight of Cs is 132.91 grams per mole.See the Web Links to the left of this answer for a periodic table with more information about this element! Isotopes Atoms of the same element with different numbers of neutrons. Where more than one isotope exists, the value given is the abundance weighted average. It is a soft, silvery-gold alkali metal with a melting point of 28 °C (82 °F), which makes it one of only five elemental metals that are liquid at or near room temperature. Classified as an alkali metal, Cesium is a solid at room temperature. The atomic number of cesium (Cs) is 55. 0. See answer SINAZEUS SINAZEUS Atomic mass= number of protons + number of neutrons hope this helps . spideylover10 spideylover10 Answer: 133. View cesium.docx from CHE 121 at Clinton High, Clinton. The name is derived from a Latin word Caesius which means sky blue, as it burns with a blue flame.