A sample of Cesium is 75.00% with a mass of 133.00 amu, 20.00% with a mass of 132.00 amu, and 5.000% with a mass of 134.00 amu. What is its average atomic mass?

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

answer; the numbers of valence electrons in the acetic acid molecule (ch3co2h) is 24;