Scerri just doesn't particularly care. This unfortunately became more and more obvious as the class progressed. At first I was impressed by his obvious intelligent and occasional dry humor, but he is not a good professor. He speeds at a breakneck pace through a vast array of material without giving any context as to how concepts relate to each other or why we should care. Additionally, his lecture slides are spotted with typos and are almost entirely useless to review afterwards, so you need to take expansive notes. On the positive side, the Owl homework is very forgiving, and is a substantial part of your final grade. I learned pretty much nothing through the majority of the class, and had to frantically study outside materials and previous tests to make any measurable progress as tests drew near. While this landed me with very good scores, it was not a particularly comfortable or rewarding way to go through class. Through all of this, Scerri speeds on, unconcerned with the fact that 90% of the students have no real clue what's going on.
Anyway, the long and the short of it is this: avoid Scerri if humanly possible, especially if you are not strong in chemistry coming in. My previous knowledge was the only thing allowing me to do well, and things would have been far more hellish in an already brutal class if I had not had experience going in.

If you can avoid scerri I would strongly suggest doing so. He is just plain mean. It is clear he has a big ego from the start of the class and expects his students to understand difficult topics with poor explanation. He really just shouldn't be a teacher. It is clear he doesn't care for student's success and makes students feel dumb for asking questions. I stopped going to lecture pretty early on because he covers content so ridiculously fast that there was no way I could keep up. What I found helped is watching the recorded lectures and taking meticulous notes and pausing to look up topics I didn't understand right away. Unfortunately this will not be enough to succeed in this class, especially if you have not taken AP chemistry. It is important you find a good TA, I was stuck with a TA that wasn't very good and so I started going to my friends discussion sections and that was more helpful. FIND A GOOD STUDY GROUP. Scerri's tests are very conceptual and he expects you to memorize the most niche parts of lecture that aren't even relevant to the class or chemistry in general which makes it really hard to study for the tests. He also down curved the first midterm which was pretty upsetting. This is definitely a weeder course so if you are in it good luck. Most of the TA's I talked to said this content was ridiculously hard for an intro course and when he introduces Schrodinger's equation in quantum mechanics it is comical. His slides are full of typos which is frustrating. I even found a mistake in one of his past finals which was super annoying because he doesn't post any type of answer key so you have no idea if you are doing the problems the right way. Scerri also provides very little practice problems in lecture and the OWL homework isn't relevant to the content he tests you on. Overall I hated this class and I hate Scerri and I'm so glad I never have to take one of his classes again.

Rough class, but I think it's reflective of what weeder prerequisite college classes are like. If you took a ton of AP classes in high school, it's definitely possible to get an A. I pretty much ignored my other classes and solely studied for this one which was how I managed to get an A.

Lectures: VERY FAST. It might feel discouraging, but TAKE NOTES. Even if they're sloppy or not perfect get a pen to paper and try to follow. If you don't take notes, you're going to have a lot harder of time trying to grasp concepts later on. Also---the things Scerri verbally mentions during the lecture are often the minute details he expects you to remember during exams.

Slides: Straight up memorize these. However, take note of the slides/concepts you don't need to know (he just adds them for curiosity sake lmao). For everything else though, if it's on the slides it will probably be on the exams.

Owl Quizzes: These are just problems he assigns online. They're an awesome grade booster, but aside from that completely useless. Scerri himself told us that they're not reflective of what's on the exam and are usually harder than the exam content. Complete them periodically so you don't fall behind.

Exams: Two midterms + one final. Half problems were free response and half were multiple choice. Exams seem difficult at first, but are possible to master. Ask around for test banks/past exams from classmates. I did 4 full practice exams before each midterm and the same for the final and got good scores (in the A- and B+ range). For problems you don't understand, STOP and spend as long as you need to understand them; it's worth it. By the time I took the exam I predicted basically all of the problems so there were no surprises. TAs were also super graceful with the free response and give generous partial credit. Also---our final had absolutely no spectroscopy, if that's helpful.

TAs: I had Dimitri, and he was a God send. These TAs know exactly what's on the exam, and they're willing to tell you if something is on the exam or not (just ask).

Office Hours: Scerri's office hours were always so packed; people were sitting on the floor and in the doorway. TA office hours are better.

Scerri himself is an extremely knowledgable scientist---not quite a skillful professor. I think the reason why he has such awful ratings is because fall quarter freshmen are taking this class and aren't used to the difficulty/pace/dynamic of college courses. Don't expect your hand to be held. Once you get the hang of how college classes work you'll be fine. Sit near the front at the beginning and find a study group; they'll be a lifesaver. Good luck, you'll need it.

Scerri is a good lecturer and professor. In class, he often goes through the material at a rapid pace so it's hard to learn in class unless the concept is really easy. He doesn't have his lectures recorded which makes you show up to class. Despite general confusion in lecture, this is where discussions bridge the gap between what was taught in class and what you retained. The class was easy if you were able to cover the material after lecture and understand what was going on. You will need to study for the tests, if you don't, expect to fail.

Lectures: Attend every lecture because if you don't you will have to learn the concepts on your own from the slides and it will be much harder. Scerri is able to explain the concepts well and, lacking this, will make it much harder to learn.

Discussion: It really doesn't matter which discussion you go to. If your TA sucks, go to the other TA's. The more TA's you go to, the more practice you will have before the midterm/final. Each TA will give you a deeper understanding of the concepts and from a different perspective. I went to every TA discussion in the week and found that even if I already understood what was going on, it was beneficial.

Office Hours: I never went, but I've heard they're helpful.

Tests:
The tests are relatively difficult and you should prepare by using the test bank, reading the book, and doing the owl questions(BEFORE the test). From what I've gathered, he likes to ask at least one extra challenging question on the test. The tests aren't impossible but if you've never encountered the question before it's going to be difficult to figure out the correct answer. The formula sheet he gives doesn't cover all the questions as some you have to memorize to get correct (derivations or recall). The content comes from what he's discussed in lecture so really no surprise there, you just have to understand what was going on. There was only one midterm this quarter and I think the average was a B/B-. Studying for 2 days straight going over the released midterms and memorizing them until the early hours of the morning paid off and that was enough to succeed on the test.

For the Final: Thoroughly go over as many finals as you can get your hands on. Most of the questions are small revisions if not the exact same question from other finals. If you know how to run through a question, you will be able to do so on the final. I noticed he liked to repeat rather challenging questions that students often got a 0 or partial on. Study those challenging ones so you will be able to answer them if they appear.

Grading: He grades the class on a curve. You can't do average and expect to get an A. You have to work harder than 90% of the class if you want to score as such. You won't find out how well you did on the final until the next quarter. The grade you see is the curved grade, not the grade on your final.

a lot of the reviews here bash scerri and the class but it’s about as hard as you’d expect a college-level (weeder) chem class to be. i studied hard and it was doable. (not easy, doable.)

grade distribution: for my quarter, it was 30% hw (easy 100%), 30% midterm, 40% final. the midterm and final themselves weren’t curved but the final grade was. (iirc it was a downgrade :( ). no extra credit.

lectures: scerri goes really fast in lecture which was def a struggle to keep up with but i HIGHLY HIGHLY recommend going to his office hours. he’ll go over material again and again and you can ask follow up questions, which you can’t really do in lecture. he’s also not that scary. he actually has a sense of humor (i know, how surprising) also, he usually stays behind lecture for a few minutes to answer questions. even if you don’t have questions, i recommend you hang out there so if someone else asks a question, you can benefit from the answer.

homework: the class uses owl for homework assignments, which has lots of attempts and you can keep coming back to it. it’s due at the end of the quarter but don’t fall behind cuz it takes forever. one problem is that the owl questions aren’t even what you’re expected to know for the course, so just speedrun them and you’ll be fine. (it’s an easy 100% so do not mess up. it’ll put you at a huge disadvantage for the final curve). other than owl, there’s no other hw.

exams: for exams, scerri does reuse so many old questions. do as many of his past exams as possible and that’ll set you up really well for the midterm and final. he posts a couple on bruinlearn but see if you can find others (like at the test bank, etc.). don’t start studying too late — there’s so much to study.

your ta will usually have practice questions for you to do. if you want more practice, other tas also sometimes post their questions on bruinlearn, so you can check that out.

also, this course is def not just like ap chem since it does cover some quantum stuff. it is complicated and you will have to work at it, but find a good study group, engage with the material, and you’ll be able to do it.

good luck!!!

I agree with most of the negative reviews. My philosophy to a happy life is to try avoid thinking about this class and the professor as much as possible so all I'm going to highlight is that it is evil to have the midterm and final on Sundays. I missed meeting Timothee Chalamet at the Wonka premiere because of him... That alone... is evil. When I hear the words "Schrodinger's" or "quantum" it's like I'm a soldier waking up to trumpets in the break of dawn. Avoid this class as much as you can. I put my entire chest into this class and got As in all of my other classes, but this one really takes the cake. What do you gain by curving down grades? CHEM 20A with Prof Scerri is the mysterious looming figure that haunts me in my sleep. But I digress. I feel like I got all the content down if I'm being honest... he just seems... a bit unfair. If they're trying to weed me out... they almost got me. To the C+ I got, thank you for allowing me to pass. But I hope to never see you or anything lower than you again. THEY CAN TRY TO WEED ME OUT BUT YOU'RE GONNA HAVE TO TRY HARDER! IF YOU EVER SEE ME FIGHTING A GRIZZLY BEAR.. HELP THE BEAR!

DO NOT TAKE HIS CLASS! HE IS THE WORST! YOU WILL FAIL AND CRY AND SUFFER!

dude this class was bad... scerri is incomprehensible and terrifying. the course is reasonably difficult (what you'd expect for a chemistry class) but scerri is a terrible teacher and is entirely unclear about what he wants you to know.
the homework is fine- its a bunch of modules due at the end of the quarter. totally manageable but not really helpful for exams.
the ta's are helpful for the most part. sometimes they seemed to be just as lost about how scerri approaches certain topics, and will just teach you a different way. theyre as helpful as they can be with what theyre given, and i definitely suggest going to discussion. attendance isnt taken for discussion or lecture so you can pick which TA you like.
ive heard that other sections of 20a have much better professors. do everything you can to avoid scerri. his slideshows make absolutely no sense and wont walk you through the kinds of problems youll see on the exams. he's going to be incredibly vague about what will be on the exams and what info he will give you on the formula sheet. he doesnt really stop for questions and will make you feel stupid if he doesnt like your question. he's really terrible at gauging how his students are feeling or how much we're learning. the first lecture about quantum mechanics will be comically difficult and scerri will simply push through.

shits tough. cant wait to take a chemistry class with a decent professor.

I hated this class and only did well out of spite for Scerri

I don't recommend this class to anyone who wants to maintain an interest in chemistry. If you have to take this class with him here is the rundown:
HOMEWORK: As of Winter 2020 he uses OWL for homework. It 's like 10 online "quizzes". All the homework is due at the end of the quarter and it's free points basically because they give you 10 tries on the same with different numbers/elements and tell you how to get the answer if you get it wrong. Unlimited time on every "quiz".
TEXTBOOK: There is a textbook that comes with OWL. I never used it.
LECTURES: Possibly the worst part of the class. Not bruincasted, and he posts the Powerpoints but they make no sense. Like actually ZERO sense. Worst formatting on earth, barely any insightful content. When he goes through them in class, there is slightly more clarity. Slightly. He is not a great explainer for complex topics, moves rather fast for no reason, and does not answer questions well. After the first midterm (Week 3), I stopped taking notes and attended intermittently.
TESTS: These are his only saving grace LMAO. Purely based on previous tests. Your TAs should give you a packet of his previous exams. LITERALLY just do these and memorize them and tests are a breeze. Only caveat is most of them do not have the answers so check with someone or ask your TAs if you want.
TAs: I believe this is where you'll get the most actual learning. My TA was not that great, so I attended other TA sections. They can be pretty helpful and are usually better teachers than Scerri himself. If you don't life your TA, DEFINITELY try the others. Attendance didn't really matter at all.

TLDR; don't take this class. if you have to just make sure you go to TA sections and do the past exams.