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secondary 3 | A Maths
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hi could someone explain how this qn is done?
Date Posted: 3 years ago
Views: 361
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ah i see. but how would i know how to draw the diagram?coz my cher never teach abt drawing diagrams like the one you have drawn.
i will upload another more detailed explanation then. Hopefully, you will learn.
ok thank you!
Dear Anonymous, I just upload an article with link on the different between oxidation states and valency. Some might supply you with misleading information. Sometimes, it sound professional. But....?
http://www.dynamicscience.com.au/tester/solutions1/chemistry/chemicalequations/valency.html
" Group 6 elements, have 6 valence electrons and will tend to take 2 electrons and have a valency of -2. "
This is for people who are grossly unaware of different conventions used in chemistry :D
" Group 6 elements, have 6 valence electrons and will tend to take 2 electrons and have a valency of -2. "
This is for people who are grossly unaware of different conventions used in chemistry :D
Just take note. Certain 'tutors' are blind to different conventions and only insist on their way.
Especially those unknown ones who claim to be professional and quote some websites.
For this qn, you don't really need to know Valency.
Even at the highest level, scientists often debate which is wrong or right.
The IUPAC definition of valency is not used universally, just like we don't see the IUPAC nomenclature being used in many industries.
Especially those unknown ones who claim to be professional and quote some websites.
For this qn, you don't really need to know Valency.
Even at the highest level, scientists often debate which is wrong or right.
The IUPAC definition of valency is not used universally, just like we don't see the IUPAC nomenclature being used in many industries.
https://www.thoughtco.com/definition-of-valence-in-chemistry-604680
By Anne Marie Helmenstine, Ph.D.
Updated January 24, 2019
Valence is typically the number of electrons needed to fill the outermost shell of an atom. Because exceptions exist, the more general definition of valence is the number of electrons with which a given atom generally bonds or number of bonds an atom forms. (Think iron, which may have a valence of 2 or a valence of 3.)
Common Valences
Atoms of elements in the main group of the periodic table may display a valence between 1 and 7 (since 8 is a complete octet).
Group 1 (I) - Usually displays a valence of 1. Example: Na in NaCl
Group 2 (II) - Typical valence is 2. Example: Mg in MgCl2
Group 13 (III) - Usual valence is 3. Example: Al in AlCl3
Group 14 (IV) - Usual valence is 4. Example: C in CO (double bond) or CH4 (single bonds)
Group 15 (V) - Usual valences are 3 and 5. Examples are N in NH3 and P in PCl5
Group 16 (VI) - Typical valences are 2 and 6. Example: O in H2O
Group 17 (VII) - Usual valences are 1 and 7. Examples: Cl in HCl
Valence vs Oxidation State
There are two problems with "valence". First, the definition is ambiguous. Second, it's just a whole number, without a sign to give you an indication of whether an atom will gain an electron or lose its outermost one(s). For example, the valence of both hydrogen and chlorine is 1, yet hydrogen usually loses its electron to become H+, while chlorine usually gains an additional electron to become Cl-.
The oxidation state is a better indicator of the electronic state of an atom because it has both magnitude and sign. Also, it's understood an element's atoms may display different oxidation states depending on the conditions. The sign is positive for electropositive atoms and negative for electronegative atoms. The most common oxidation state of hydrogen is +8. The most common oxidation state for chlorine is -1.
By Anne Marie Helmenstine, Ph.D.
Updated January 24, 2019
Valence is typically the number of electrons needed to fill the outermost shell of an atom. Because exceptions exist, the more general definition of valence is the number of electrons with which a given atom generally bonds or number of bonds an atom forms. (Think iron, which may have a valence of 2 or a valence of 3.)
Common Valences
Atoms of elements in the main group of the periodic table may display a valence between 1 and 7 (since 8 is a complete octet).
Group 1 (I) - Usually displays a valence of 1. Example: Na in NaCl
Group 2 (II) - Typical valence is 2. Example: Mg in MgCl2
Group 13 (III) - Usual valence is 3. Example: Al in AlCl3
Group 14 (IV) - Usual valence is 4. Example: C in CO (double bond) or CH4 (single bonds)
Group 15 (V) - Usual valences are 3 and 5. Examples are N in NH3 and P in PCl5
Group 16 (VI) - Typical valences are 2 and 6. Example: O in H2O
Group 17 (VII) - Usual valences are 1 and 7. Examples: Cl in HCl
Valence vs Oxidation State
There are two problems with "valence". First, the definition is ambiguous. Second, it's just a whole number, without a sign to give you an indication of whether an atom will gain an electron or lose its outermost one(s). For example, the valence of both hydrogen and chlorine is 1, yet hydrogen usually loses its electron to become H+, while chlorine usually gains an additional electron to become Cl-.
The oxidation state is a better indicator of the electronic state of an atom because it has both magnitude and sign. Also, it's understood an element's atoms may display different oxidation states depending on the conditions. The sign is positive for electropositive atoms and negative for electronegative atoms. The most common oxidation state of hydrogen is +8. The most common oxidation state for chlorine is -1.
https://www.thoughtco.com/what-is-valence-or-valency-606459
https://www.ibchem.com/IB16/03.22.htm
"To find whether an atom takes a positive or negative valency consider the electronegativity of the atom to which it is attached.
In nitrogen dioxide, NO2, oxygen is MORE electronegative than the nitrogen and so the nitrogen takes a positive valency (in this case = +4).
In ammonia, NH3, nitrogen is MORE electronegative than the hydrogen, so it is the nitrogen that takes the negative valency (in ths case -3)."
"To find whether an atom takes a positive or negative valency consider the electronegativity of the atom to which it is attached.
In nitrogen dioxide, NO2, oxygen is MORE electronegative than the nitrogen and so the nitrogen takes a positive valency (in this case = +4).
In ammonia, NH3, nitrogen is MORE electronegative than the hydrogen, so it is the nitrogen that takes the negative valency (in ths case -3)."
done
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This is a reminder to all students to be wary of unverified people on this platform. They may not give you correct information. Especially those who do not have their credentials listed. Sometimes, they are oblivious to different conventions and only think their way is right.
Aways check their workings for errors. These people also tend to misunderstand your comments and queries.
Aways check their workings for errors. These people also tend to misunderstand your comments and queries.
Date Posted:
3 years ago
you put in a lot of effort against that guy HAHAHA
This is what happens when one tries to be a smart alec and is not receptive to others comments.
mhmm yes true
Oh by the way, there were a number of occasions where he misread the question or wrote incorrect steps/mixed up terms. I caught those mistakes and he just subtly deleted and reposted...
ohh I see
I guess he could have been more polite with his argument
coz the way he phrased it was a bit rude lah
Indeed. Been very civil with this person up till recently. Then he decided to say that his time is wasted and claim that others are 'making trouble', 'mis-concept' when he himself did not interpret my comments correctly.
Beware of such people. Like to jump to conclusions and are very assertive.
Did you know that he tried to do long division for one of the math questions, without realising that it was division by 0?
Beware of such people. Like to jump to conclusions and are very assertive.
Did you know that he tried to do long division for one of the math questions, without realising that it was division by 0?
https://ask.manytutors.com/questions/116676
I indicated a possibility of an issue with that and he still went on and on.
I indicated a possibility of an issue with that and he still went on and on.
oh wow. being open minded to other's ideas seems like something he is not very good at. hope he changes
he changed his name to NotATutor lol
Trying to be funny and throwing shade at others. Very immature and childish.
Yet, he still can call me boy. Hahaha.
Yet, he still can call me boy. Hahaha.
Anyway if you need math help, you can pm me on telegram.
I'll try to help if I'm free.
Username : @mathandscience1
I'll try to help if I'm free.
Username : @mathandscience1
oh tysm, really appreciate it :)
No prob
ahh I understand that thanks
The signs of your valency are missing.
For example, O is -2
For example, O is -2
Dear Anonymous, I just upload an article with link on the different between oxidation states and valency. Some might supply you with misleading information. Sometimes, it sound professional. But....?
Sure.
For someone that said ln² x is wrong to Zwen without verifying that his/her lecturer is using other convention, I'm pretty sure you're very reliable...
Oh yea, 1E99 when the maximum average is 4.
Not even a registered tutor here, I wonder how credible you are..
Byjus.com has already been flagged numerous times for inaccuracy, I wonder how reliable it is...
Anonymous, refer to the link I posted.
For someone that said ln² x is wrong to Zwen without verifying that his/her lecturer is using other convention, I'm pretty sure you're very reliable...
Oh yea, 1E99 when the maximum average is 4.
Not even a registered tutor here, I wonder how credible you are..
Byjus.com has already been flagged numerous times for inaccuracy, I wonder how reliable it is...
Anonymous, refer to the link I posted.
Dont waste my time. Go back study how valency is defined. Stop giving ppl trouble.
You're the one that's wasting others time.
Unverified user. Do you even have any professional qualifications? Especially in this subject?
Trying to correct Eric Nicholas K on his usage of 'curve' when it is obviously accepted at O level?
Joke.
Unverified user. Do you even have any professional qualifications? Especially in this subject?
Trying to correct Eric Nicholas K on his usage of 'curve' when it is obviously accepted at O level?
Joke.
Most important. Stop giving misleading info
Tell that to Zwen when you told her ln² x is wrong... HAHAA
There is a huge different between the cases. When I found out that some ppl do write it differently, i stopped insisting. This case is an obvious mistake yet continue to argue. Anyway from this incidence i know more about a person. Will try not to hurt your feeling again. Will only direct my msg to students. Anyway, no enemies! Next time before trying to find fault on me, do more revision first.
Sure, stop insisting. But did you actually correct yourself? Did you fact check first?
How about you do more revision first?
①What you're talking about is IUPAC's definition.
Valence or Valency has different definitions and different conventions in Chemistry.
The one that you talk about is the one that doesn't have a sign.
② In the other convention, the sign (+/-) is used to indicate whether the atom of interest's shared electrons are closer to itself (more electronegative than the other atom which shares electrons with it) or the opposite.
The goal is to achieve the stable noble gas configuration.
In the IUPAC definition for example , O is given valency of 2 for covalent bonding as in the case of H2O
But when you consider that in H2O the O atom is more electronegative, the electrons are closer to O and is given -2.
"If the most electronegative element is assigned a negative valency and the most electropositive element a positive valency then the sum of the atoms' valencies must equal zero."
https://www.ibchem.com/IB16/03.22.htm
③And very frequently, valency is taken to be synonymous with oxidation number, (even though this might not always hold true)
The IUPAC definition of valencyalso doesn't account for elements that exhibit more than 1 oxidation state eg. Fe²+, Fe³+
④ Valency can also be taken to mean the number of outermost electrons (in the valence shell) an atom has.
For O, this is 6.
So in summary,
Valency is but a vague term which shouldn't be covered at this level at all.
Read it yourself here and find the sources yourself.
https://en.m.wikipedia.org/wiki/Valence_(chemistry)
https://www.thoughtco.com/what-is-valence-or-valency-606459
(PhD author)
Are you going to say that IUPAC naming is the only correct one and other names for chemicals are wrong by the same vein?
Scientists can't even agree on what the proper definition is (that IUPAC one was last given in 1994).
https://goldbook.iupac.org/terms/view/V06588
So don't come and tell me to do my revision when you yourself are not well versed in this.
'obvious mistakes' ? Sure.
Inflexible 'tutors' like you who only 'know the way you do things' don't help students at all.
Learn to be more humble and don't think you know it all. Pot calling the kettle black.
Next time before you tell people to do their revision first , do your own.
People like you will only make enemies everywhere with your egoistic comments and shade-throwing.
How about you do more revision first?
①What you're talking about is IUPAC's definition.
Valence or Valency has different definitions and different conventions in Chemistry.
The one that you talk about is the one that doesn't have a sign.
② In the other convention, the sign (+/-) is used to indicate whether the atom of interest's shared electrons are closer to itself (more electronegative than the other atom which shares electrons with it) or the opposite.
The goal is to achieve the stable noble gas configuration.
In the IUPAC definition for example , O is given valency of 2 for covalent bonding as in the case of H2O
But when you consider that in H2O the O atom is more electronegative, the electrons are closer to O and is given -2.
"If the most electronegative element is assigned a negative valency and the most electropositive element a positive valency then the sum of the atoms' valencies must equal zero."
https://www.ibchem.com/IB16/03.22.htm
③And very frequently, valency is taken to be synonymous with oxidation number, (even though this might not always hold true)
The IUPAC definition of valencyalso doesn't account for elements that exhibit more than 1 oxidation state eg. Fe²+, Fe³+
④ Valency can also be taken to mean the number of outermost electrons (in the valence shell) an atom has.
For O, this is 6.
So in summary,
Valency is but a vague term which shouldn't be covered at this level at all.
Read it yourself here and find the sources yourself.
https://en.m.wikipedia.org/wiki/Valence_(chemistry)
https://www.thoughtco.com/what-is-valence-or-valency-606459
(PhD author)
Are you going to say that IUPAC naming is the only correct one and other names for chemicals are wrong by the same vein?
Scientists can't even agree on what the proper definition is (that IUPAC one was last given in 1994).
https://goldbook.iupac.org/terms/view/V06588
So don't come and tell me to do my revision when you yourself are not well versed in this.
'obvious mistakes' ? Sure.
Inflexible 'tutors' like you who only 'know the way you do things' don't help students at all.
Learn to be more humble and don't think you know it all. Pot calling the kettle black.
Next time before you tell people to do their revision first , do your own.
People like you will only make enemies everywhere with your egoistic comments and shade-throwing.
Who told you i am a tutor? I do not ever ask student to go for tution if they don't really understand. Come on boy. I will not compete with you for students. No worry. Giving a helping hand itself worth million$.
Jumping to conclusions.
No one needs to compete with you. Don't think you're some big shot please. What a big ego.
If I need students, I won't be here. The students here mostly come for free answers and are not interested to get tuition.
Telling them to get a tutor is for their well-being, because it is a consistent source of help, not something like this platform where no everyone will answer your students and there aren't many people familiar with the marking scheme and guidelines. Qualified tuition resources are especially important.
It is not telling them to get ME as a tutor. So how about you stop jumping to conclusions and actually read comments properly.
It's not some money-grubbing hint to the student (like you imply I'm trying to get students)
Boy? How old are you even? to be calling me this?
All you can do is hide behind an anonymous profile. Sorry to say but your credibility is suspect.
No one needs to compete with you. Don't think you're some big shot please. What a big ego.
If I need students, I won't be here. The students here mostly come for free answers and are not interested to get tuition.
Telling them to get a tutor is for their well-being, because it is a consistent source of help, not something like this platform where no everyone will answer your students and there aren't many people familiar with the marking scheme and guidelines. Qualified tuition resources are especially important.
It is not telling them to get ME as a tutor. So how about you stop jumping to conclusions and actually read comments properly.
It's not some money-grubbing hint to the student (like you imply I'm trying to get students)
Boy? How old are you even? to be calling me this?
All you can do is hide behind an anonymous profile. Sorry to say but your credibility is suspect.
And you, as someone who wants to educate others, should learn to accept others perspectives or opinions.
Not brush it down as 'waste time'.
Educators/assistants should not be inflexible it will not do the student any help.
Also, telling me that I had a misconception with regards to normal approximation, when you actually misinterpreted my comment in the first place.
Buck up on your comprehension skills dude.
Not brush it down as 'waste time'.
Educators/assistants should not be inflexible it will not do the student any help.
Also, telling me that I had a misconception with regards to normal approximation, when you actually misinterpreted my comment in the first place.
Buck up on your comprehension skills dude.
While you r make so much effort trying to talk nonsense, i having been continuing helping students! Come on. Let it down! You can't be as kind hearted. Once, u have a motive behind u, u will get emotional. I will rather dedicate my time to help students rather than talking with you. THE END...
Rubbish. I've been on this platform since 2017, consistently answering questions along with other regulars like AC Lim, Eric , Arnold , etc.
We don't get money from this and neither do I need.
Also we don't do advertising of rates and phone numbers on their posts, unlike what some other tutors here do.
You're but a newbie...
We don't get money from this and neither do I need.
Also we don't do advertising of rates and phone numbers on their posts, unlike what some other tutors here do.
You're but a newbie...
The only motive I and other regular long-timers like Eric and Arnold is to assist these students in the correct and most suitable way. As well as to share perspectives and opinions positively. Not like you.
You implying and suggesting that others are being financially motivated only shows that you're having this warped thinking yourself.
So get off your moral high horse, dude.
Casting aspersions on one's integrity and accusing others of having ulterior motives serves nothing to improve your inflexible and dogged mindset.
And what's with that self-praise? Kind hearted? You? Oh what a megalomaniac.
Well done , Yong Kc. Sullied your own name and your family's too.
And don't use the excuse of spending time to help other students to deflect questions asked about your logic and arguments.
Poor showing.
The only one who is dogmatic and talking nonsense is you.
ln²x ≠ (ln x)² ? Biggest joke ever.
You implying and suggesting that others are being financially motivated only shows that you're having this warped thinking yourself.
So get off your moral high horse, dude.
Casting aspersions on one's integrity and accusing others of having ulterior motives serves nothing to improve your inflexible and dogged mindset.
And what's with that self-praise? Kind hearted? You? Oh what a megalomaniac.
Well done , Yong Kc. Sullied your own name and your family's too.
And don't use the excuse of spending time to help other students to deflect questions asked about your logic and arguments.
Poor showing.
The only one who is dogmatic and talking nonsense is you.
ln²x ≠ (ln x)² ? Biggest joke ever.
https://iupac.org/projects/project-details/?project_nr=2018-030-2-200
"The semantics of valence in chemistry is the ability of an atom to bond. In English, valence appears in several different quantitative connotations, besides composed terms like covalence, bond valence, and valence bond. For a numerical parameter, existence of alternative values due to differing perceptions is undesirable and obscures communication.
This project objective is to find out whether a comprehensive definition of valence can be formulated."
Still tell people to do revision first...
"The semantics of valence in chemistry is the ability of an atom to bond. In English, valence appears in several different quantitative connotations, besides composed terms like covalence, bond valence, and valence bond. For a numerical parameter, existence of alternative values due to differing perceptions is undesirable and obscures communication.
This project objective is to find out whether a comprehensive definition of valence can be formulated."
Still tell people to do revision first...
And what makes you think byjus.com is a reliable source?
Mr Anonymous Yong Kc?
Doesn't take a genius to know that oxidation state is different from valencies and there are different conventions for valency
Mr Anonymous Yong Kc?
Doesn't take a genius to know that oxidation state is different from valencies and there are different conventions for valency
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