Lots of data skipped or erroneous: The 4004, was Intel's first. (and mentioned)... Okay the 4040 came next as an upgraded 4004. Okay then came the 8008, the first 8-bit processor for Intel. Now came the 8080, and like the 4040 was an improvement to the 4004, the 8080 was an improvement to the 8008, okay. Now.. What I don't see mentioned is these chips all required multiple voltages to run. A few Intel people seen room for improvement and left to start Zilog (the Z80, which in itself was very popular, is heavily based on the 8080, but only needed a single voltage to operate.) Intel countered quickly with the 8085.
Now, the 8086 was indeed the first 16-bit CPU from Intel, and the 8088 was pretty close to it. The only real differences between these two CPUs is the 8088 made use simpler and cheaper than the 8086 as it dropped down to an 8-bit data bus. (No other real changes.) Which came first? The 8086 in '78 and the 8088 in '79. The 80186 and 80188 were not very popular and were buggy. the [80]286 followed and was a hit as it didn't have the same bugs as the 186 and backed off slightly on problematic integrations, keeping the ones that worked and fixing the ones they could.
Now some clarifications. the 386 was a 32-bit CPU. The 386SX was the same CPU but with a pared down 16-bit data bus.(As mentioned already the 386SL was closer to the 286 bus and had features for power saving.) Shortly after the 386 took on the DX suffix to be called a 386DX. ALL Intel CPUs up through the 386 series relied on another chip for floating point from the 8086/8088 through the 386. It was similarly numbered, but the last digit was a 7.
Okay, the 486 included the FPU and had other improvements, unless there were flaws in the 486's FPU, which to save on losses, became the 486SX (FPU disabled) while the 486DX had a fully functional FPU on board. The 487 was just a re-pinned 486DX.
Then, alas, came the Pentium, so named as they couldn't trademark a CPU name that was just a series of numbers (the 486 family was still technically called a 80486, and Intel's competition was using the numbers to identify their compatible CPUs. Intel didn't like it. Tried a law suit and lost, then changed the naming convention to a word name.)