In the previous blog post of the Periodic Table Mini Series, we have discussed about the properties of a special group of elements in the Periodic Table – known as Metalloids.

Today, we will look into the Group I elements, also known as the Alkali Metals.

All the Group I elements have the following common properties:

• Soft & Silvery solids
• Low densities and low melting points
• React vigorously with cold water to form an alkaline solution of the metal hydroxide  and hydrogen gas
• Burn brightly when heated in chlorine gas to give a white solid metal chloride product
• Atoms of Group I elements have 1 electron in their outer shells
• Atoms of elements tend to form cation with a charge of +1 in compounds

If you are asked in Chemistry Exams / in Chemistry Tuition Class / by your Chemistry Teacher / by your Chemistry Tutor – on predicting properties of other Group I elements, remember this 2 points:

• Based on Known Properties of Lithium, Sodium and Potassium
• The changes down the group

and this brings us into looking at the trends of Group I elements,

Generally, as We Go Down The Group:

• Melting points of elements decrease
• Elements become more reactive

Let us check out a GCE O Level Examination Question:

Francium (atomic number 87) is in Group I of the Periodic Table.

(i) Suggest the physical appearance of Francium

(ii) How would you expect the melting point of francium to compare with that of sodium?

(iii) Suggest with an equation, what would be observed if a piece of francium is put into cold water? Explain what happens to the pH of the solution produced.

Let us check out some common errors made by many students in O Level Chemistry Examinations, before i provide you with the correct answers (suggested) – this has proved to be effective in learning the correct Chemistry Concepts by students, based on feedbacks from those that have purchased Up Your Chemistry Grades Now!

Students’ Common Answers:

(i) It is a silvery hard solid since it is a metal.

(ii) It is lower than sodium.

(iii)It would reactive to produce an alkaline solution and hydrogen gas.

2Fr  +  2H2O  –> 2FrOH  +  H2

The pH of the solution would be alkaline.

Let us see how the student(s) fare..

Examiners / Markers’ Comments:

(i) Wrong answer by student. Group 1 metals is indeed silvery solid, but it is soft, NOT hard! Many students did not realise that Group 1 metals are soft. NOT ALL metals are hard. Group 1 is the exception.

(ii) Answer is not complete to gain the full marks. You must give a reason to support your prediction. Better answer would be: “Francium has a lower melting point than sodium, since it is lower then sodium in Group 1.

(iii)The chemical equation is correct. But the student will loose marks in his/her answers. He/She did not mention that Francium will EXPLODE with added to cold water, since Group 1 metals get more reactive down the group. He/She also did not mention that the pH would be around 12-13, which is like sodium hydroxide – a strong alkali.

Hope you find the above discussion to be helpful towards your learning of Chemistry in a more effective & efficient manner.

Until the next post…

As we are preparing to welcome the festive Lunar New Year, GCE O Level students (that took O Level Exams in  2008) will be equally excited about their posting results.

The Ministry of Education (MOE) will be releasing the posting results for the 2009 Joint Admissions Exercise (JAE) and the Joint Polytechnic Special Admissions Exercise (JPSAE) next friday 30th Jan 2009 at 8am.

Students can get their posting results at:

JAE website

JPSAE website

or call 6691-2131

And for those who has given their mobile number during the registration will receive an SMS informing them of their posting.

Posting Lists will also be displayed at Junior Colleges across Singapore and the Millenia Institute.

All The Best! Hope you manage to get the course / college that you have aimed for!

Hello everyone,

In less than a week time, all Chinese worldwide celebrates the brand new lunar year!

I would like to take this chance to wish you and your loved ones a prosperous new year.
Better grades, better health, better relationship, better experiences and more importantly
a better you for this brand new year!

HAPPY LUNAR NEW YEAR 2009!

Wish you a Happy & Prosperous New Year!

For those that understand Mandarin / Chinese, check out this video:

For those that do not understand Mandarin / Chinese, check this video instead:

PS: I look forward in serving you more ‘goodies’ in your mastery of O level Chemistry!

PPS: By the way, for local students, the schedule for Secondary 3 classes (limited seats) will be announced after Chinese New Year. Stay Tuned!

GONG XI GONG XI GONG XI NI!

Just a quick note to local students taking their GCE O Level Chemistry Exams in Year 2009:

Chemistry Coaching for Sec 4: 3 2 seats available for Friday 7 – 9pm class

>> Click Here to sign up immediately & join the class immediately *

Chemistry Coaching for Sec 3: New class starting in March

>> Click Here to Pre-Register & Enjoy Early Bird Subscriber “Registration Fee Waiver”

For organisations/schools that are interested to invite us for Coaching / Speaking Engagements, please drop us an email to admin@SimpleChemConcepts.com.

PS: Rmbr what the 2008 GCE O Level student said: “Consistent Hardwork & Regular Revision” must start early. There is no magic to doing well for Chemistry.

For readers following this blog, if you are also taking Math (be it A-Math or E-Math) examinations in GCE O Levels as well as other equivalent Maths’ examinations (ICGSE, IB, etc), you will be excited about this post.

Ai Ling ONG, the founder for www.singaporeolevelmaths.com (voted # 1 website for “O Level Math Tips” in Google, Yahoo, MSN search engines) conducted a survey/poll last Dec to check if her subscribers would like to have “F*REE Monthly Math Exam Papers + Answer Keys). The polling results was an astonishing 98% YES, and Ai Ling has just announced the 1st Math Exam-Paper Download on her website as well as the RSS feed.

So for you readers, if you are doing Math, check out this AWESOME Gift by Ai Ling.

PS: If you are not aware, www.singaporeolevelmaths has been made our official online learning partner since Nov 08.

PPS: For those taking Physics – do stay tuned for 2009. I might have something for you too. Keep your fingers crossed.

In the previous blogpost on Periodic Table Mini Series (Part II), we have discussed on the main Features of The Periodic Table. Today we are going to continue with another important feature of The Periodic Table.

METALLOIDS:

Bold line divides the elements into Metals (LHS) & Non-Metals (RHS), as shown above.

Tip to rmbr: Bold line starts by separating the Metallic Al & Non-Metallic B

Several elements located near bold line

• Known as Metalloids
• Have properties of Metals & Non-Metals
• Commonly used in the Semi-Con Industry to make computer chips
• Example: Silicon & Germanium

(Image by snowfan)

Here are 2 questions for you to work on:

Question 1:
In which GROUP & PERIOD is Germanium and Silicon located in the Periodic Table?

Question 2:
What is the commonality / similarity between Germanium & Silicon?

PS: Try it out and leave down your suggested answers (and explanations) in the section “LEAVE A REPLY” directly below this blogpost, and we will come in to discuss the correct answers.

Yesterday i mentioned why it is important to understand the topic on Periodic Table well, in order to score well for GCE O Level Chemistry Examination. I have also posted 2 exam-based questions on Features & Trends in the Periodic Table.

In the next few days, i am gog to blogpost on Periodic Table Mini Series by sharing Chemistry Tips & Strategies with discussions on exam-based questions.

For now, let us look into the

Features of the Periodic Table:

• Elements in the Periodic Table are arranged in order of increasing proton number.

Period:

• 7 Horizontal Rows of elements, numbered 1 to 7
• Each element in a period has a proton number which is 1 < the element after it
• As we move from LEFT –> RIGHT of the Periodic Table
  => Metallic character of the elements ?
  => Non-metallic character ?
• Elements in the same period contains same number of electron shells

Group:

• 8 Vertical columns of elements in the Periodic Table, numbered I to VIII (or 0)
• Elements in the same group
  => Same number of valence electrons
  => Similar chemical properties

Hope you are already learning something. Now is your time to participate in order to accelerate your learning.

Question 1:
Which statement about the Periodic Table is false?
a. Elements get more metallic on descending a group
b. Elements in the same group have the same number of valence electrons
c. From left to right across a period, there is a change from non-metallic to metallic
d. Elements are arranged in order of increasing proton number

Question 2:
In the Periodic Table, how many periods include the elements of atomic numbers 1-18?
a. 2
b. 3
c. 6
d. 8

PS: Try it out and leave your suggested answers & explanations in the “LEAVE A REPLY” section right below this post.