For ACS data - is there a way to tell which codes are valid for tracts vs block group?

Some codes work for both, some return "null" when the block-group level is queried.

For example, the following url works for the tract level:
http://api.census.gov/data/2010/acs5?key=4be82289939444f20513cd7c3c3eafb42e0d9ccf&get=B06007_003E,NAME&for=tract:*&in=state:08+county:059

But using the same code, it returns null for the... more »

I get nulls with the url:

http://api.census.gov/data/2011/acs5?key=*************&get=NAME,B24121_001E&for=state:*

 

I'm getting nulls for all B24121_* elements.

 

My goal is to see a list of the median salaries by occupation for each state.

 

Thank you