My 10th grader was told to memorize about 60 elements, their name and their abbreviation.
As I helped him I realized how frustrating it is that some things are so similar with the abbreviation.
To help I finally decided the way it gets into the brain does not matter, so I divided the cards up.
First I made a stack of abbreviations that are just one letter. C = Carbon
Next I made a stack of those which are the first two letters of the chemical's name. Ca = Calcium
Next I made a stack of those with two consonants which was not the first two of the chemical's name. Cr = Chromium
Lastly I made a stack of those with two letters that had absolutely nothing to do with the English word for the chemical or is tricky. Cu = Copper Au = Gold
By focusing on memorizing just the groups, my son was able to remember them.
After that, ghere are about 5% that are giving him trouble.
A few I made up silly sayings to give the answer. Sodium is Na which stumped my son. I reminded him of how much salt my father puts on his food and we tell him enough is enough and he always says, "Nah! This is good!" So Na = Sodium. Although I know that table salt is not plain Na this is good enough for the purpose.
Later when they were all jumbled up he remembered them correctly. So long as the item is retained in the memory how it got in does not matter. If the info is retrieved by the brain correctly then learning has taken place.