Are you serious? Chem, Bio and physics?!?
You can take 4 electives but they won't allow you to take chem, bio and physics together, there won't enough time.
You have 4 periods a day, lasting 1.5 hours each.
Literature, HOI, Maths 1 takes up 3 hours( 1 lecture and 1 tute) each
Drama takes up 1.5 hours
EAP takes up 3 hours a week
Chem takes 4.5 hours(2 lectures and 1 tute) and 3 hour practical every alternate week
Bio and physics takes up 3 hours(1 lec, 1 tute) and 3 hour practicals every alternate week
That makes up 24 hours of lectures and tutorials every week and 9 hours of practical every alternate week. That is called suicide.
This is still possible, but you'll end up with only 2 free periods every alternate week. And, practicals ARE very stressful. In terms 2+3, the HOI essays come in and you are required to research on the topics in the libraries.
Below is the list of assignments throughout the year:
Term 1-nothing
Term 2-HOI essay(1200 words, 20%, due in week 6), Drama monologue presentation(10% of English mark, due in week 7), EAP essay(5%, due in week 5)
Term 3-HOI essay(1500 words, 30%, due in week 6), Drama group performance(10% of English, due in week 7), EAP essay(5%, week 5), Chemistry presentation(10%, week 7)+winter
Term 4-Drama group performance(10% of English, week 7), EAP presentation(25%, due in week 2)
As you can see, term 3 is hell term.

If you want 4 electives, take 2 sciences, maths 1 and one other.
oh thanks... then i might drop off physics then =( but i love science subjs xD oh well, what to do. I only have 24 hours a day.