How to use the Periodic Table given in the exam

Every SPM Chemistry paper comes with a Periodic Table printed inside it. Many students glance at it once and never use it again, which is a wasted resource. The table is not decoration, it is a tool that hands you relative atomic masses, electron arrangements, ion charges and a way to check your own answers. Learning to read it quickly means you carry less in your head and make fewer slips. Everything here builds on the Periodic Table of elements, so revise that chapter alongside these tips.

What each box actually tells you

For every element, the printed table gives you three things: the symbol, the proton number (usually the smaller number), and the relative atomic mass (usually the larger number). The proton number tells you how many protons, and in a neutral atom, how many electrons, the element has. The relative atomic mass is what you use in every mole calculation. Get into the habit of reading which number is which before the exam so you never confuse them under pressure.

Never memorise relative atomic masses, read them

This is the single biggest time-saver. You do not need to memorise that oxygen is 16 or copper is 64, because the table gives them to you. When a calculation question appears, find the element on the table and read its relative atomic mass straight off. Use those values to work out relative molecular masses and molar masses, as shown on our relative atomic mass page. Reading the value takes five seconds and removes a whole category of careless errors.

Getting electron arrangement from position

The table’s layout is a map of electron arrangement, and you can read it two ways:

• The period (row) tells you the number of occupied shells. An element in Period 3 has three shells.
• The group (column) tells you the number of valence electrons for the main groups. A Group 1 element has 1 valence electron; a Group 17 element has 7.

So for an element in Period 3, Group 2, you know it has three shells with 2 electrons in the outer shell, arrangement 2.8.2. You can rebuild an electron arrangement from position alone, without memorising every element, and check it against the proton number.

Predicting the charge on an ion

For the main-group metals and non-metals, the group predicts the ion charge, which is priceless when you are writing formulae:

• Group 1 forms +1 ions, Group 2 forms +2 ions, Group 13 forms +3 ions.
• Group 15 forms -3, Group 16 forms -2, Group 17 forms -1.
• Group 18 (noble gases) are unreactive and do not normally form ions.

If a formula question involves calcium and chlorine, the table reminds you calcium is Group 2 (+2) and chlorine is Group 17 (-1), so the formula must be CaCl₂. That is a check you can do in seconds.

Metals, non-metals and the transition block

The table also shows you at a glance where the metals and non-metals sit, metals on the left and middle, non-metals on the upper right, with the dividing staircase between them. The block in the middle is the transition metals, which often form coloured compounds and more than one ion charge. If a question hands you an unfamiliar element, its position tells you roughly how it should behave.

Same group, similar chemistry

One more thing the columns tell you: elements in the same group have similar chemical properties, because they have the same number of valence electrons. That is why all Group 1 metals react with water in the same way and all Group 17 elements form similar salts. If a question describes an unfamiliar element in Group 1, you can predict its behaviour from the group you already know. The table quietly lets you reason about elements you have never studied in detail.

Practical habits for the exam room

• Circle the elements named in a question on the printed table so you can find them again quickly.
• Read the relative atomic mass for every calculation rather than trusting memory.
• Use the table as a checker, after writing a formula or an electron arrangement, glance back and confirm the group and period agree with what you wrote.
• Practise this while doing calculation questions so it becomes automatic, and try our interactive SPM Periodic Table to get comfortable with the layout.

The mindset

The Periodic Table given in the exam is there to reduce how much you must memorise, not to test whether you memorised it. Treat it as a reference you actively consult, and it will quietly protect several marks in every paper, the relative atomic masses you might have misremembered, the ion charges you might have guessed, the electron arrangements you might have slipped on. If reading the table quickly still feels awkward, that is exactly the kind of habit a teacher can build with you in a short session. Our online one-to-one lessons run in English from RM50 an hour, with a paid one-hour trial.