In the previous blogposts in this Periodic Table Mini Series, we have discussed on the common errors that students made when they are answering questions that are related to the Periodic Table. We have also discussed what the examiners want – i.e. what you need to write in order to score the full marks in that question. Hope you have benefited from the tips given. If you are looking for more of such “Student’s Common Errors Made” and “What Examiners Are Looking Out For in Exam”, you might want to check out Up Your Chemistry Grades Now! which was officially launched since last October, and have sold to more than 9 countries since.
Today, we will finish up Periodic Table Mini Series with an Examination Tips.
In Chemistry Exams, you are commonly being asked to predict the properties of an unknown element.
What you can do is to find the nearest element in the same group which you are familiar with. The unknown element will have almost the same properties as the familiar element.
Question:
For Barium (Ba),
(a) How would you expect it to react with cold water and what would you expect to be the pH of the solution produced?
(b) What would you expect to be the formula of its oxide?
&
Suggested Solution:
The nearest familiar element to Barium is Calcium. Thus:
(a) Just like calcium, it should react quickly with cold water and produce an alkaline solution with a strong pH, as well as liberation of Hydrogen Gas.
(b) BaO, just like we commonly have CaO (slaked lime)
This strategy always work when you encounter such questions in Chemistry Exams.
Hope you have been learning something in this mini series of Periodic Table.
Until the next post.