I have a MacBook Pro 13-inch, Mid 2012 and one of its RAM slots appears to have been damaged (The computer restarts when moved too much). So I can only have one RAM module in it. I was reading on Apple's website for changing RAM: https://support.apple.com/en-us/HT201165#1.
They state that my computer is only able to have a maximum of 8GB RAM.
My question is, can I have a single RAM module with 8GB instead of 2x 4GB RAM modules as they mention on the website?
For the MacBook Pro 13-inch, Mid 2012, Apple only officially supports 8 GB RAM, 2 - 204-pin PC3-12800 (1600 MHz) DDR3 SO-DIMM; however, it can actually support 16 GB. So in theory you should be able to use a single 8 GB PC3-12800 (1600 MHz) DDR3 SO-DIMM.
You can purchase a single Crucial 8GB Single DDR3/DDR3L 1600 MT/s (PC3-12800) SODIMM 204-Pin Memory For Mac - CT8G3S160BM from Amazon, currently $48.17 USD.
OWC Memory 8.0GB PC12800 DDR3L Module, currently $45.99 USD.
Crucial 8GB DDR3L-1600 SODIMM Memory for Mac from Crucial, currently $49.99 USD.
Have a look at the iFixit MacBook Pro 13" Unibody Mid 2012 RAM Replacement Guide.