There are two types of dependents, "Qualifying
Children"(QC) and standard ("Qualifying Relative" in IRS
parlance even though they don't have to actually be related). There is no income
limit for a QC but there is an age limit, a relationship test and residence
test. Only a QC qualifies a taxpayer for the Earned Income Credit and the Child
Tax Credit. They are interrelated but the rules are different for each.
There is an additional age requirement for the $2000 Child tax credit (CTC). The QC must be under age 17.
So, a Qualifying relative dependent and a qualifying child, over 16, only gets you the $500 (non-refundable) "Dependent credit", not the $2000 Child tax credit
