Periodic table with IGCSE facts
This table uses the same relative atomic masses as the Periodic Table printed in the IGCSE Chemistry exam (for example Cl = 35.5, Cu = 64). Tap an element to see its details and the facts IGCSE questions ask about.
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Atomic number 11 · Relative atomic mass 23 · Period 3 · Group I
Protons 11 · neutrons (using Ar as the mass number) 12 · electrons 11 (2,8,1)
Flame test: yellow. Reacts vigorously with cold water, fizzing and moving on the surface.
Group I, the alkali metals: soft metals with low density and low melting points. Reactivity increases down the group (lithium → sodium → potassium). They react with water to give an alkaline hydroxide solution and hydrogen gas.
Values as printed on the IGCSE Chemistry 0620 data sheet (Cl = 35.5, Cu = 64). Tap an element for its details.
Reading the table
- The group (column) tells you the number of outer-shell electrons for Groups I to VII. Group VIII (the noble gases) have a full outer shell.
- The period (row) tells you the number of electron shells.
- Metals are on the left and in the middle, non-metals on the right. Going across a period, elements change from metallic to non-metallic.
Trends to know
- Group I: reactivity increases down the group.
- Group VII: reactivity decreases down the group, and colour gets darker.
- Transition elements: coloured compounds, catalysts, ions with different charges.
Questions students ask
Why is chlorine 35.5?
Chlorine has two common isotopes, chlorine-35 and chlorine-37. The relative atomic mass is the average mass weighted by how common each isotope is.
Do I get a periodic table in the exam?
Yes, every IGCSE Chemistry paper includes the Periodic Table with relative atomic masses.