Periodic Trends Worksheet

Print the worksheet, or quiz on screen: pick the atom with the largest radius or highest ionization energy.

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  1. 1.Which has the largest atomic radius: Lithium, Beryllium, Oxygen or Fluorine? They are all in period 2.
  2. 2.Which has the smallest atomic radius: Beryllium, Magnesium, Calcium or Strontium? They are all in group 2.
  3. 3.Which has the largest atomic radius: Sodium, Aluminum, Sulfur or Chlorine? They are all in period 3.
  4. 4.Which has the smallest atomic radius: Lithium, Sodium, Rubidium or Cesium? They are all in group 1.
  5. 5.Which has the largest atomic radius: Potassium, Germanium, Arsenic or Bromine? They are all in period 4.
  6. 6.Which has the smallest atomic radius: Beryllium, Magnesium, Strontium or Barium? They are all in group 2.
  7. 7.Which has the largest atomic radius: Potassium, Calcium, Gallium or Arsenic? They are all in period 4.
  8. 8.Which has the smallest atomic radius: Oxygen, Sulfur, Selenium or Polonium? They are all in group 16.
  9. 9.Which has the largest atomic radius: Carbon, Nitrogen, Oxygen or Fluorine? They are all in period 2.
  10. 10.Which has the smallest atomic radius: Nitrogen, Phosphorus, Antimony or Bismuth? They are all in group 15.
  11. 11.Which has the largest atomic radius: Rubidium, Strontium, Tellurium or Iodine? They are all in period 5.
  12. 12.Which has the smallest atomic radius: Fluorine, Chlorine, Bromine or Iodine? They are all in group 17.
  13. 13.Which has the largest atomic radius: Cesium, Barium, Bismuth or Astatine? They are all in period 6.
  14. 14.Which has the smallest atomic radius: Nitrogen, Phosphorus, Arsenic or Antimony? They are all in group 15.
  15. 15.Which has the largest atomic radius: Rubidium, Strontium, Tin or Tellurium? They are all in period 5.
  16. 16.Which has the smallest atomic radius: Aluminum, Gallium, Indium or Thallium? They are all in group 13.
  17. 17.Which has the largest atomic radius: Cesium, Barium, Lead or Polonium? They are all in period 6.
  18. 18.Which has the smallest atomic radius: Lithium, Potassium, Rubidium or Cesium? They are all in group 1.
  19. 19.Which has the highest first ionization energy: Aluminum, Sulfur, Chlorine or Argon? They are all in period 3.
  20. 20.Which has the lowest first ionization energy: Oxygen, Selenium, Tellurium or Polonium? They are all in group 16.
  21. 21.Which has the highest first ionization energy: Lead, Polonium, Astatine or Radon? They are all in period 6.
  22. 22.Which has the lowest first ionization energy: Argon, Krypton, Xenon or Radon? They are all in group 18.
  23. 23.Which has the highest first ionization energy: Beryllium, Oxygen, Fluorine or Neon? They are all in period 2.
  24. 24.Which has the lowest first ionization energy: Magnesium, Calcium, Strontium or Barium? They are all in group 2.
  25. 25.Which has the highest first ionization energy: Strontium, Indium, Tin or Iodine? They are all in period 5.
  26. 26.Which has the lowest first ionization energy: Sodium, Potassium, Rubidium or Cesium? They are all in group 1.
  27. 27.Which has the highest first ionization energy: Sodium, Magnesium, Sulfur or Chlorine? They are all in period 3.
  28. 28.Which has the lowest first ionization energy: Beryllium, Magnesium, Strontium or Barium? They are all in group 2.
  29. 29.Which has the highest first ionization energy: Cesium, Barium, Thallium or Polonium? They are all in period 6.
  30. 30.Which has the lowest first ionization energy: Fluorine, Bromine, Iodine or Astatine? They are all in group 17.
  31. 31.Which has the highest first ionization energy: Rubidium, Strontium, Tin or Antimony? They are all in period 5.
  32. 32.Which has the lowest first ionization energy: Phosphorus, Arsenic, Antimony or Bismuth? They are all in group 15.
  33. 33.Which has the highest first ionization energy: Boron, Oxygen, Fluorine or Neon? They are all in period 2.
  34. 34.Which has the lowest first ionization energy: Carbon, Silicon, Germanium or Tin? They are all in group 14.
  35. 35.Which has the highest first ionization energy: Potassium, Germanium, Arsenic or Bromine? They are all in period 4.
  36. 36.Which has the lowest first ionization energy: Chlorine, Bromine, Iodine or Astatine? They are all in group 17.
  37. 37.Which has the highest electronegativity: Aluminum, Silicon, Sulfur or Chlorine? They are all in period 3.
  38. 38.Which has the lowest electronegativity: Magnesium, Calcium, Strontium or Barium? They are all in group 2.
  39. 39.Which has the highest electronegativity: Aluminum, Phosphorus, Sulfur or Chlorine? They are all in period 3.
  40. 40.Which has the lowest electronegativity: Nitrogen, Phosphorus, Antimony or Bismuth? They are all in group 15.
  41. 41.Which has the highest electronegativity: Indium, Tin, Antimony or Tellurium? They are all in period 5.
  42. 42.Which has the lowest electronegativity: Oxygen, Sulfur, Tellurium or Polonium? They are all in group 16.
  43. 43.Which has the highest electronegativity: Potassium, Calcium, Gallium or Arsenic? They are all in period 4.
  44. 44.Which has the lowest electronegativity: Fluorine, Chlorine, Bromine or Iodine? They are all in group 17.
  45. 45.Which has the highest electronegativity: Strontium, Indium, Tin or Tellurium? They are all in period 5.
  46. 46.Which has the lowest electronegativity: Beryllium, Magnesium, Strontium or Barium? They are all in group 2.
  47. 47.Which has the highest electronegativity: Lithium, Carbon, Nitrogen or Oxygen? They are all in period 2.
  48. 48.Which has the lowest electronegativity: Fluorine, Chlorine, Iodine or Astatine? They are all in group 17.
  49. 49.Which has the highest electronegativity: Lithium, Carbon, Nitrogen or Fluorine? They are all in period 2.
  50. 50.Which has the lowest electronegativity: Nitrogen, Arsenic, Antimony or Bismuth? They are all in group 15.
  51. 51.Which has the highest electronegativity: Potassium, Gallium, Selenium or Bromine? They are all in period 4.
  52. 52.Which has the lowest electronegativity: Boron, Gallium, Indium or Thallium? They are all in group 13.
  53. 53.Which has the highest electronegativity: Cesium, Barium, Bismuth or Astatine? They are all in period 6.
  54. 54.Which has the lowest electronegativity: Oxygen, Sulfur, Selenium or Tellurium? They are all in group 16.
  55. 55.Put Lithium, Sodium, Potassium and Rubidium in order of atomic radius, lowest first.
  56. 56.Put Potassium, Calcium, Germanium and Bromine in order of atomic radius, lowest first.
  57. 57.Put Fluorine, Chlorine, Bromine and Iodine in order of atomic radius, lowest first.
  58. 58.Put Lithium, Carbon, Oxygen and Neon in order of first ionization energy, lowest first.
  59. 59.Put Beryllium, Magnesium, Calcium and Strontium in order of first ionization energy, lowest first.
  60. 60.Put Sodium, Silicon, Chlorine and Argon in order of first ionization energy, lowest first.
  61. 61.Put Helium, Neon, Argon and Krypton in order of first ionization energy, lowest first.
  62. 62.Put Lithium, Boron, Nitrogen and Fluorine in order of electronegativity, lowest first.
  63. 63.Put Fluorine, Chlorine, Bromine and Iodine in order of electronegativity, lowest first.
  64. 64.Put Sodium, Magnesium, Phosphorus and Chlorine in order of electronegativity, lowest first.
  65. 65.Put Oxygen, Sulfur, Selenium and Tellurium in order of electronegativity, lowest first.
  66. 66.Across a period from left to right, how does atomic radius change?
  67. 67.Down a group, how does atomic radius change?
  68. 68.Across a period from left to right, how does first ionization energy change?
  69. 69.Down a group, how does first ionization energy change?
  70. 70.Across a period from left to right, how does electronegativity change?
  71. 71.Down a group, how does electronegativity change?
  72. 72.Across a period from left to right, how does metallic character change?
  73. 73.Down a group, how does metallic character change?
  74. 74.What is effective nuclear charge?
  75. 75.Which electrons shield an outer electron from the nucleus most?
  76. 76.Why do atoms get smaller from left to right across a period?
  77. 77.Why do atoms get larger down a group?
  78. 78.Which element is the most electronegative?
  79. 79.Which group has the lowest electronegativities?
  80. 80.Why are the noble gases usually left out of electronegativity tables?
  81. 81.Where on the periodic table are the most electronegative elements?
  82. 82.Which has the higher first ionization energy, Beryllium or Boron?
  83. 83.Which has the higher first ionization energy, Nitrogen or Oxygen?
  84. 84.Which has the higher first ionization energy, Magnesium or Aluminum?
  85. 85.Which has the higher first ionization energy, Phosphorus or Sulfur?
  86. 86.Boron is to the right of beryllium, yet its first ionization energy is lower. Why?
  87. 87.Oxygen is to the right of nitrogen, yet its first ionization energy is slightly lower. Why?
Which element is the most electronegative?

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Unofficial practice questions, not affiliated with any school, textbook publisher or worksheet maker. Bank checked September 23, 2026.

Next step Ordering done. Now place all 118 elements on the tableWhere do beryllium and boron sit? Place the first 20

How it works

This periodic trends worksheet asks how elements compare, not where they sit: which atom is largest, which holds its outer electron hardest, which pulls shared electrons most. Every answer shows the listed values and the reason.

Read the full guide

Six sets

Start with the trend set: which way radius, ionization energy, electronegativity and metallic character run, and why. Then three comparison sets, one per property, and a set that puts four elements in order. The last set is the exceptions, such as boron after beryllium.

Rule of thumb, checked against data

Every comparison uses main-group elements from periods 2 to 6, and was kept only where the trend and the listed values agree for all four atoms. The explanation prints those values, so you can see the gap.

  • Radius and ionization energy run opposite ways: the biggest atom in a row holds its outer electron most loosely.

Questions and answers

Does this atomic trends worksheet come with answers?

Yes. Each question shows the right choice, the reason and the values once you check it, and the list under the quiz gives every answer. Print a set with its key, or save it as a periodic trends worksheet pdf from your browser's print window.

What are the main periodic trends?

Across a period from left to right, atomic radius and metallic character decrease while first ionization energy and electronegativity increase. Down a group each of those reverses. The cause across a row is a rising effective nuclear charge; down a group, an extra shell.

Why are noble gases missing from the radius and electronegativity questions?

Noble gas atoms usually do not share electrons, so electronegativity tables leave them out, and their listed radius is measured a different way from the bonded atoms around them. They do appear in the ionization energy questions, where they hold the highest values.

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