Now I have the following command, but these command does not work:
/tellraw @p ["",{"text":"Click here","color":"aqua","clickEvent":{"action":"run_command","value":"/give @p diamond 2"},"clickEvent":{"action":"run_command","value":"/give @p diamond 2"}},{"text":" for 2","color":"none"},{"text":" diamonds","color":"blue"}},{"text":"!","color":"none"}]
Is it possible to place 2 commands in one "word"?
It is not possible to have two clickEvent tags on the same word. Among other things, it's not valid JSON. So you can't do it this way.
However, you can use /trigger to achieve a similar effect (though you will need several command blocks). You'd need to have several command blocks that first run the commands you want on players with a specific scoreboard value and then clear that scoreboard value.