Yes, it should work.
Yes, it should work.
Visit the page at asrock.com/support/cpu.asp?s=AM4 for more details.
It doesn't work together. The motherboard only works with 3rd to 5th generation chips, while the CPU is from the 2nd generation. Consider upgrading to a 3rd or 4th generation Ryzen CPU—they're cheaper. The Ryzen 5 5600 offers great value, or a lower generation G series if you're still budgeting for a GPU.
The listing doesn't match the 'a520' board according to the compatibility chart provided by @PDifolco.