There is no agreement about either the birth year or birth place for Chen Tuan. I have seen claims of Luyi County now in Henan province (red region on the map) as well as Haozhou in Hao County of Anhui Province (green region on the map) so probably some where in the yellow rectangle.
After the Tang Dynasty (started in 618) crumbled in 907 there was a period of considerable political and military chaos known as the Five Dynasties and Ten Kingdoms. The Northern Song dynasty was established in 960 and went on to forcefully reunify China for the next 20 years. Chen Tuan is described as having died in 989, but is said to have traveled for some years after failing the scholar’s examination, then lived for about 20 years at Wudang Mountain and later as a hermit in Huashan at the First Year of Xiande Period of Later Zhou Dynast (951- 960). This would seem to indicate a birth year of 910.