Question

Count the number of neutrons in Cesium-130/55 (Cs) A. 55 B. 75 C. 130 D. 185

Answer 1

The answer to the question is letter B which is 75. Cesium or also called as cesium is a chemical element with the symbol Cs. It is a silvery-gold element which is soft alkalai metal with melting point of 28.5 C. 

Answer 2

the given element is

¹³⁰₅₅Cs

the superscript - 130 is the atomic mass / mass number

mass number is the sum of protons and neutrons

subscript - 55 is the atomic number

atomic number is the number of protons

therefore we can write the following equations

protons = 55

protons + neutrons = 130

so neutrons = 130 - protons

nuetrons = 130 - 55 = 75

number of neutrons = 75