Pre-Chem is just a Pre-major designation that means you are not a Full Chemistry major until you complete the required courses with a 2.0 to declare the major. If you do not meet the requirements for the Pre-major, then you cannot complete your Chemistry degree by taking the rest of the Chemistry major courses.
Pre-Major courses and units:
Chemistry 1A or 2A, 1B or 2B, 1C or 2C- 9 units
Chemistry 1AL, 1BL or 2BC, 1CL or 2CC - 6 units
Chemistry 6AL, 6BL (or 6BH) - 6 units
Chemistry 109A or 109AH, 109B or 109BH, 109C or 109CH - 12 units
Math 3A-B, 4A -12 units
Physics 1-2-3-4 - 14 units