Command Bloc Issue with : coordinates + tellraw

Here's the problem :
I got my /tellraw comman block. Here's the code :

/tellraw @a[20002,120,20001,r=250] {"",{"text":" > Island PvP < ","color":"yellow"},{"text":"La partie débute dans 20 secondes !","color":"aqua"}}

But there's an error that say :

[02:30:34] Invalid json: Expected name at line 1 column 2

What does it mean ?