If there are no order at the price of at exactly $2000 or higher than that, you will not be able to sell any size of your 1 bitcoin.

Also, remember that it is not the whole bitcoin that buyers can buy from your sell order.
They could order minimum trading amount of the exchanger with respect yo your Bitcoin; they could order like 0.001bitcoin @ $2000 that means 0.001 btc will be successful from your sell order. Leaving you with a pending 0.999 btc sell order.