chemistry qssss
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Hi, here a few qs to ask.
What's the difference between O'levels and A'levels chemistry huh?
(2) Let's say a chemical equation. 2H^2 = 4H??
Like this also can ah, as in the balancing part of a chemical equation.
(3) Periodic table Grp 1 grp 2 then suddenly jump over all the transition metals then grp 3. So transition metal is all grp what? -
O levels chem is really really the basic.
A levels chem is hell (70% memorizing).
2H^2 = 4H
yes this is balanced.
when balancing, you must balance the elements AND the charge.
transition metals have no group, i think.
transition metals are defined as elements which can form one or more ions with incompletely filled d-orbitals.
EDIT:
there are apparently 18 groups in total according to wiki:
http://en.wikipedia.org/wiki/Periodic_table_group
so the transition metals have groups after all... (we didnt learn that in A levels) -
thanks for the ans bro.
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(1) The difference between O levels and A levels chemistry is something like your PSLE and Sec 4 Maths, except that without your O levels Chemistry, your A levels Chemistry is as good as dead.Originally posted by Qex:Hi, here a few qs to ask.
What's the difference between O'levels and A'levels chemistry huh?
(2) Let's say a chemical equation. 2H^2 = 4H??
Like this also can ah, as in the balancing part of a chemical equation.
(3) Periodic table Grp 1 grp 2 then suddenly jump over all the transition metals then grp 3. So transition metal is all grp what?
(2) Cannot. There's no such thing as (2H)^2 = 4H. The 'power' is not applicable in the arithmetic sense in chemistry. Superscripts are used to denote the charge of the species and subscripts are used to denote the number of that particular species.
(3) To understand this, you need to read up on how electron subshells are filled up.
Basically, during your O levels, you do remember that Potassium and Calcium have a 'weird' electronic configuration of 2,8,8,1 and 2,8,8,2 instead of 2,8,9 and 2,8,10. This is because of certain subshells are filled up first (more specifically, your s subshells are filled up before your d subshell of the same principal quantum subshell).
At A levels chemistry, you will learn about the electron subshells and how they are filled up. Your periodic table actually gives you a pretty good guide of which shells are filled up in which order as each particular section of elements are due to filling up of certain subshells (eg first 2 groups are s subshells, transition elements are due to d subshells, groups 3 to 8 (or 13 to 18 if u include transition metal groups) are due to p subshells, lactinides and actinides are due to f subshells etc.
I hope that pretty much answers your questions. -
Yar. A level got include atomic orbital s,p,d,f etc..
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I am just wondering why does Chemistry syllabus always mislead us
In O level you learn a electronic configuration and draw a dot and cross diagram.
In A level you scrap out the O level electronic config and learn the orbital version with s, p, d, f. and you learn lewis structure, hybridization etc
In higher level (uni), you are told that lewis structure is wrong and dot and cross is wrong. From the uncertainty principle, we can't determine the position of election accurately so the Bohr's model is out.
There is no hybridization taking place. instead the AO interact to form MO and the shape is determined by the point groups and symmetry operations.
d orbitals rarely interact and delta bond is rarely formed. (I guess only in Ligand field theory where delta bond will be involved in bonding) -
O Level mah. Just gives you a rough idea only.Originally posted by ultranova3:I am just wondering why does Chemistry syllabus always mislead us
In O level you learn a electronic configuration and draw a dot and cross diagram.
In A level you scrap out the O level electronic config and learn the orbital version with s, p, d, f. and you learn lewis structure, hybridization etc
In higher level (uni), you are told that lewis structure is wrong and dot and cross is wrong. From the uncertainty principle, we can't determine the position of election accurately so the Bohr's model is out.
There is no hybridization taking place. instead the AO interact to form MO and the shape is determined by the point groups and symmetry operations.
d orbitals rarely interact and delta bond is rarely formed. (I guess only in Ligand field theory where delta bond will be involved in bonding)