Hey there,
You are correct that you do not have to count your chemistry mark, however, I think you might be a bit confused about the way admission averages work (or I could just be totally misunderstanding you).
When applying to university , it is not simply your top six marks that count, nor do you get to choose which of your marks contribute to your admission average. Rather, the grades that correspond to the required courses for your program of interest that make up your admission average.
The admission requirements for iSci are as follows:
Completion of High School Diploma including the following Grade 12 U/M requirements:
• English (ENG4U)
• Advanced Functions (MHF4U)
• Calculus & Vectors (MCV4U),
• Two of: Biology (SBI4U), Chemistry (SCH4U), Physics (SPH4U)
• One additional 12 U/M course
In your case the grades that would contribute to your admission average would be English, Advanced Functions, Calculus and Vectors (which you have not indicated that you are taking. As this is a requirement for the program, you will need to take this course to be considered for admission to the program), Biology, Physics and Computer Science.
In this case your Chemistry grade does not count towards your average as the iSci program only requires two 12U sciences. Your Computer Science would then fill up the final slot (assuming that it is a U or M level course). This should not impact your chances of getting in, in any way (although I am no expert on university admissions). Students have been admitted to the program (myself included) who have not completed all three 12U sciences.
Hopefully this is clear, I know the university application process is quite confusing, with different schools/programs having different requirements.
Again, keep in mind that Calculus and Vectors is a required course that you will need to take. Also, remember that admission to the iSci program is not solely based on grades, and also requires the completion of a supplementary application. This will be found on the iSci website closer to the application deadline.
Best of luck!
Lori