The atomic number of cesium (cs) is 55. if an atom of cesium has 78 neutrons, what is the atomic mass of cesium?

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

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be