bought one stick by accident

Solution
For one thing, another mistake you made was purchasing DDR4-2400Mhz RAM when your motherboard only supports 2133Mhz memory. Secondly, 2 sticks would allow the sticks to run in dual channel, i.e. theoretically double the bandwidth, but in reality this has little performance boost since all the bandwidth is rarely ever used.

Point be told, it'll work, you'll still have 8GB, but your RAM will run at a lower frequency and in single channel.
For one thing, another mistake you made was purchasing DDR4-2400Mhz RAM when your motherboard only supports 2133Mhz memory. Secondly, 2 sticks would allow the sticks to run in dual channel, i.e. theoretically double the bandwidth, but in reality this has little performance boost since all the bandwidth is rarely ever used.

Point be told, it'll work, you'll still have 8GB, but your RAM will run at a lower frequency and in single channel.
 
Solution