Hi everyone,
It is a brand new year and we will continue where we left off last year, on sharing more:
- Chemistry Phenomenons (show how abstract chemistry concepts are linked to our everyday life)
- Chemistry Tips (simplify chemistry theories in bit-size, concise points for easier understanding)
- Chemistry Strategies (discussion on exam-based tough questions and the strategy to answer it)
For the last two fridays, i was focused on coaching a group of committed Sec 4 students (under the Chemistry Ultimate Leap Programme 09) on the topic of Periodic Table & Trends.
(Chemistry Coaching in one of our training rooms)
Majority of the students have gone through this topic in their schools before, and found it lame redundant for us to talk about it. From their expressions, indirectly it signals to me that i should be coaching them on other topics instead.
I am glad i held my fort (and i always do! ) and continue with the topic, because i realized that their understanding of the topic is not anywhere strong enough, to handle GCE O Level Exam Questions (this is clearly the case based on their scores/marks in their PreReview Tests, before i formally start the academic coaching session).
Now, let’s get this straight..when we mention Periodic Table, it is the “Bible” of Chemistry. You need to know the following well:
- Features of the Periodic Table
- Trends in the Periodic Table
- Group I elements’ Properties (Physical/Chemical) & Trends (down the group)
- Group VII elements’ Properties (Physical/Chemical) & Trends (down the group)
- Group O elements’ Properties (Physical/Chemical) & Trends (down the group)
- Transition Metals’ Properties (Physical/Chemical)
Comprehensive understanding of the above is crucial, as Periodic Table are usually linked to other topics, and there is no way a chemistry students can run away from it.
In fact, i expect GCE O Level students to score high FULL marks for any questions related to Periodic Table. This is a basic chapter and you need to score well here, in order to do well overall in Chemistry Exams.
Starting with this blogpost, i will be sharing & discussing tricky exam-based questions on Periodic Table & the strategies to work out the correct answers – through Periodic Table Mini Series (series of blogposts)
Let’s check out a couple of exam-based questions related to Periodic Table:
Question 1:
Boron and aluminium are both in Group III of the Periodic Table.
Which statement is true for these two elements?
a. Both elements are metals
b. Both elements contain 3 electrons in their outermost shells
c. Both elements form acidic oxides
d. Both elements have the same proton number
Question 2:
Silver (Ag) resembles Group I elements in some properties.
Which property of silver is NOT typical of Group I?
a. Silver atoms have one outermost shell electron
b. Silver forms a chloride with formula, AgCl
c. Silver conducts electricity
d. Silver is resistant to corrosion by steam
PS: Do your best to work out your answers! I will share my suggested answers + explanations, when i see people participating (cos learning can only be effective when you participate 100%).
PPS: You can write your (suggested answers + explanations) in the “LEAVE A REPLY” section right below this post.
Stay tuned to next blogpost on Periodic Table Mini Series, where i will share more Chemistry Tips & Strategies on Periodic Table, and discussed more tricky exam-based questions. For now, you can check out the ARCHIVES (previous blogposts discussions) on Periodic Table HERE
Until next post, take care!
Q1. Answer is (b) since all elements in a particular group have the same number of valence/outermost electrons.
Q2. Answer is (d) since all group 1 metal are soft metals that can easily be cut with a knife, hence, they are not resistant to corrosion(by stream), unlike silver.
I’d like to clarify some inquiries on my part. For question one, Boron is a metalloid with the properties of both metals and non-metals. Does this mean that Boron is 100% metal ? Moreover, for question 2, it really got me wondering why Ag does not have one outer most shell electron. It is known that Ag(I) has 1 valence electron. In addtion, if Ag has more than 1 valence electron, say 2 electrons, wouldn’t the product of the reaction with the chloride ion be AgCl(subscript 2) instead of AgCl ?
Q2 ans is indeed a,but i am confused in Q1 statement…..
it is mentioned in question that both are in group 3,and we know from group 1-3 all are metals then why option a cannot be correct?
This might sound a bit dumb but i am a bit confused by question 2. I thought all Group 1 metals will have only one outermost shell electron and since silver also has only one outermost shell electron, how will this be not typical of Group 1 metals?
Hi Kwee,
Let us check your reasonings:
Question 1:
Good. Dividing Line shows the B is a non-metal while Al is a metal
Aluminium forms Amphoteric Oxides, for your information.
No TWO elements can have the same proton number.
Answer is indeed (B) since both are in Group III and they have 3 valence electrons.
Question 2:
Silver is a metal – and all metals conduct electricity
Silver tends to form Ag+ cations and thus forms AgCl
Silver is very low in the Metals Reactivity Series, thus it will not displace hydrogen from steam.
Answer is indeed (A)!
Look forward to more of your participation,
Sean Chua
Master Trainer & Author
WINNERS Education Group
?Experience Learning with A Difference?
Hi Kwee,
Well done! =)
To Your Academic Success in Chemistry,
Sean Chua
Master Trainer & Author
WINNERS Education Group
“Experience Learning with A Difference”
Reasons:
1. On the right of the dividing line, all the elements are non-metals while those on the left are metals, so A is not the answer.
Since aluminium is a metal, it will not form an acidic oxide, hence C is out.
2 elements in the same group have the same number of valence electrons, so B is the answer.
2. Silver can form a chloride (Silver chloride, AgCl); B is incorrect.
Silver is a metal, so it can conduct electricity. C is out.
Silver is a very unreactive metal, so it cannot displace hydrogen from steam, so D is out. Only option left is A.
1. B
2. A