My sonata won't start and key light on dash lights up

Check your battery conections lately? could be corroted

You're not getting any spark. Start with the battery. You may not be getting a good connection. Have someone give you a jump start and see if it gets a charge. Shut off the engine, wait a about 5 minutes or so. Try to start the car. If it doesn't start then you definitely need a battery. Another old trick would be to jump start it, once the engine is running- disconnect the battery, if it stays running that rules out the alternator. Leaving the battery as the culprit.