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CChemistryPhysicsS1 to S4Atoms and the periodic table

Element explorer: atoms, isotopes and periodic trends

Everything around us is made of only about 90 kinds of atoms. Build them one proton at a time and discover the patterns of the periodic table.

⚛️Aᵣ = Σ(mass × %) ÷ 100atoms, isotopes and the periodic table
LevelS1 to S4 (and IGCSE, A Level)
TimeAbout 35 min
You useAᵣ, electron configuration, trends
PriceFree: no account

🎯 Aim

To investigate atomic structure, isotopes and the periodic trends of the first 20 elements.

You will learn to

  • Find the numbers of protons, neutrons and electrons.
  • Write electron configurations in shells and sub-shells.
  • Calculate relative atomic mass from isotope abundances.
  • Describe and explain trends across period 3.

🧭 What to do

  1. Move Atomic number Z from 1 to 20: read the shells, period and group.
  2. Choose an element in the mass spectrometer and check the calculation of Aᵣ.
  3. Choose a Property and look at the periodic trend.
  4. Compare the class data for period 3.
  5. Answer the questions with the class data.
  6. Write your conclusion and download your lab report.

🔬 Lab bench

📋 The data

Properties of the period 3 elements.

🧠 Investigate: answer from the data

Type your answer and tap Check. Use 💡 Hint first; open the method only when you are stuck.

📄 My lab report

Your report collects the aim, your data table, the graphs, your answers and your conclusion. It is made on your phone or computer: nothing is sent to anyone.

Check your conclusion

An atom has Z protons and Z electrons; isotopes differ in neutrons. Aᵣ is the weighted mean of isotope masses. Electrons fill shells (2, 8, 8) and sub-shells 1s, 2s, 2p, 3s, 3p, 4s. Across a period the nuclear charge increases, so atoms get smaller and ionisation energy and electronegativity rise; oxides change from basic to amphoteric to acidic.

➕ Get more from this experiment

📝 Free

Print the worksheet (button above), download the data, and save your report. Teachers can project this page in class.

📦 Premium Lab Pack

1 000 RWF

  • Worksheet: build a periodic table of trends from data cards
  • Atomic structure and periodicity problems
  • Teacher guide and answer key
  • Exam-style questions with marking scheme

👩‍🏫 For teachers

Use it as a practical when apparatus is missing, as homework, or as a project. Free lesson plans help you plan, teach and assess.

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