Hi, I was doing question 51 in the Zumdahl book and the last part said to calculate the atomic mass of M. When I looked in my periodic table, I couldn't find a single element with atomic symbol M. Then, I searched it up online, and it stated that the element that has a symbol of M is Molybdenum with atomic number 42. I thought that I might have not looked carefully but I looked at many periodic tables, I found out that Molybdenum's symbol is Mo. I was wondering if I read the question wrong. Here is the question if you want to get a better look at it:
51. A 1.000-g sample of a metal chloride, MCl2, is dissolved in water and treated with excess aqueous silver nitrate. The silver chloride that formed weighed 1.286 g. Calculate the atomic mass of M.

Definitely you read the question wrong.          
Kyra M is a unknown metal and you need to know its molar mass...that the question. If you know M identity from PT then this question has no meaning. You can do molar mass from the periodic table only.
Here is the planning to solve this question.
First balanced equation
2AgNO₃(aq) + MCl₂ (aq)-----> 2AgCl(s) + M(NO3)₂ (aq)
Start with what is given
g AgCl ---> moles of AgCl -----> Moles of MCl2 -----> moles of Cl- ----> g Cl-
                        g Cl- -----> g M (stop here )
                   (subtract mass of Cl- from mass of MCl₂ 1.000g
              Nest step from moles of Cl- ----> moles of M (molar ratio)
Now you are with mass and moles so work out the molar mass
Molar mass ( g/mol) = mass of M  / moles M
Can you try it Kyra?

Yes, I understand the question now. I will try to find out the answer using the planned strategy you gave me. Thank you for explaining the question to me and helping me understand it.

Hi, I am confused. I thought I had to do question 51 in chapter 4{pg 182}. In which chapter is this question?

51. A 1.000-g sample of a metal chloride, MCl2, is dissolved in water and treated with excess aqueous silver nitrate. The silver chloride that formed weighed 1.286 g. Calculate the atomic mass of M.
This is the question.