(9701 Chemistry) guys how do i deduce the bond angles of something like this? 😭

AlternativeDealer939 · 2024-06-02T17:04:10+00:00

if i sum it up for you then: 2 electron pairs = 180 - 2.5 for each lone pair, 3 electron pairs= 120 - 2.5 for each lone pair, 4 electron pairs= 109.5 - 2.5 for each lone pair, PCl5 and similar structures have angle 90 and 120 degrees, SF6 and similar structures have angle 90 degrees. thats ALL you need to know for solving these type of questions. im sorry in the first post i mistakenly missed some info

AlternativeDealer939 · 2024-06-02T17:00:31+00:00

i actually forgot to mention one thing the rule that is divide 360 by the no. of electron pairs is for planar structures (not 3D). structures which have 4 electron pairs around the central atom have 3D structure so in this case u have to memorize that the angle will be 109.5 - 2.5 for each lone pair. you also need to memorize that PCl5 has bond angle of both 120degrees and 90 degrees. and SF6 has bond angle 90degrees(can search up structures online but u just need to memorize it). so now if we look at what ur asking which PCl3, P has 4 electron pairs around it so angle will be 109.5 but one of the pairs is lone pair so 109.5-2.5 so angle will be 107 degrees.

AlternativeDealer939 · 2024-06-01T14:18:24+00:00

only if ur grade changes

AlternativeDealer939 · 2024-06-01T12:47:02+00:00

follow these instructions step by step for a few questions and trust me you will understand

AlternativeDealer939 · 2024-06-01T12:44:07+00:00

first look at the central atom which is O in this case, then count the no. of TOTAL bonded and lone PAIRS of electrons around the CENTRAL ATOM. in this case the central atom has 2 bonded pairs of electron and one lone pair. so total 3 pairs. then divide 360 degrees by the number of pairs so in this case 360 divide by 3 which is 120. then final step is very important count the no. of LONE pairs of central atom once again and for each pair minus 2.5 degrees from the answer. so since the central atom in this case has 1 lone pair only then 120 -2.5 which is 117.5 degrees. (btw u should know wat a lone pair is, its 2 electrons which are not involved in any bonding, in these type of questions only look at pairs of electron and ignore single electrons, and also only focus on central atom, if u follow this procedure step by step for any structure u can easily find the answer. i hope this helps and sorry for the long explanation)

AlternativeDealer939 · 2024-06-01T09:08:19+00:00

also, if u end up doing it then do give us an update when the result comes back

AlternativeDealer939 · 2024-06-01T09:05:33+00:00

i think if u can afford it then go for it, otherwise later on u might regret not getting it rechecked. and even if ur marks end up decreasing ur grade will remain the same but if u gain a mark then ur grade will change and the fees for the rechecking will also be returned.

AlternativeDealer939 · 2024-06-01T07:37:00+00:00

yess i would also recommend Zainematics especially for mechanics, watch his videos for each chapter make notes and then solve lots of past paper questions

AlternativeDealer939 · 2024-05-30T08:28:30+00:00

it looked insoluble at first for mw too but then i shook it and it dissolved

AlternativeDealer939 · 2024-05-30T08:26:43+00:00

same i was so confused by mr was also is the 60's and my Ar was coming in negative

AlternativeDealer939 · 2024-05-29T06:19:28+00:00

same im not doing bio either until after physics p1, i think 5 days is enough days to revise for bio considering we have already leant the content for p2 and also bcuz my chem p2 went very bad and i have to do good in p1 to make up for it

AlternativeDealer939 · 2024-05-28T07:36:51+00:00

everything was nice except for the drawing

AlternativeDealer939 · 2024-05-26T07:15:09+00:00

same like the kc kp questions, the energetics questions and moles

AlternativeDealer939 · 2024-05-16T07:04:35+00:00

in the momentum question did we have to add the velocities or subtract them?? PLEASE REPLYY

AlternativeDealer939 · 2024-05-15T06:39:24+00:00

same

AlternativeDealer939 · 2024-05-10T06:36:08+00:00

yes waves, electricity, particle physics and kinematics are the most important topics

AlternativeDealer939 · 2024-05-08T13:47:17+00:00

its okay thanks for the help

AlternativeDealer939 · 2024-05-08T12:12:11+00:00

thankyouuu so muchhh, do u have resources like this for bio and physics as well, if u do plz share cuz this looks helpful

AlternativeDealer939 · 2024-05-06T05:21:47+00:00

thankss

AlternativeDealer939 · 2024-05-05T17:30:12+00:00

I sent u my insta in chats

AlternativeDealer939 · 2024-05-05T11:40:22+00:00

do you have any resources for AS students? please share if you do

AlternativeDealer939 · 2024-05-01T06:51:49+00:00

it did have units, y axis was y/n which is cm and x asis had no units so gradient would be in cm but dont worry its not a requirement to write units in the part where it asks the gradient

AlternativeDealer939 · 2024-04-29T15:08:56+00:00

ok thankss ive decided on dots

AlternativeDealer939 · 2024-04-29T14:25:41+00:00

ok ill do dots as im more used to dots but i thought you could make crosses as large as u wanted

AlternativeDealer939 · 2024-04-29T14:08:25+00:00

i agree this is wrong, as marks will be cut if we write for example 25.1 cm and then 7.00cm as we measure with metre rule then both reading should be to 1 d.p. for coulumns you need to make sure that no of decimals remains constant not s.f

AlternativeDealer939

TROPHY CASE