Using IF Statement with Null value in Google Sheet

Questions
#1

I’m having trouble with null values. I want to use an IF statement that defines one path if the value in a Google Sheet cell is empty, and another if it is not empty. There is no “Is Null” or similar command in the expression builder. How can I do this? Thanks for any help!

#2

using expression like this.

s 98

#3

Thank you! Will give that a shot.