HELP PLEASE An individual proton has mass 1.007825 amu, and an individual neutron has mass 1.008665 amu, and the observed atomic mass gadolinium-157 is 156.92396 A. -1.38269 amu
B. 1.38269 amu
C. -1.35833 amu
D. 1.35833 amu

Because a model would make the investigation easier to understand

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic 

It conforms what ever surface its in.

What are the options? i can you if you give them.