Respuesta :

Name: Cesium
Symbol: Cs
Atomic Number: 55
Atomic Mass: 132.90546 amu
Melting Point: 28.5 °C (301.65 K, 83.3 °F)
Boiling Point: 678.4 °C (951.55005 K, 1253.12 °F)
Number of Protons/Electrons: 55
Number of Neutrons: 78
Classification:
Alkali Metal
Crystal Structure: Cubic
Density @ 293 K: 1.873 g/cm3
Color: silver
British Spelling: Caesium
IUPAC Spelling: Caesium

The atomic number of cesium = 55

So number of electron in cesium = 55

While number of protons in cesium = 55

Atomic mass of cesium= number of protons + number of neutrons  

Number of neutrons in cesium is given as 78

Atomic mass of cesium= number of protons + number of neutrons  

Atomic mass of cesium=55 + 78

                                       = 133

So, atomic weight of cesium is 133