Periodic Trends Worksheet A nswer Key
1. Circle the element with the largest atomic radius and put a square around the element with the smallest atomic radius: Cu K Ni Br Largest – K
Smallest - Br Explain why you made these choices. Atomic radius decreases as you go left to right across a period. Potassium is in the far
left group of period 4, and bromine is the farthest to the right of the four elements.
2. Circle the element with the highest ionization energy and put a square around the element with the lowest ionization energy: Cu K Ni Br Highest – Br
Smallest - K Explain why you made these choices. Ionization energy increases as you go left to right across a period. Potassium is in the
far left group of period 4, and bromine is the farthest to the right of the four elements. 3. Circle the element with the highest electron affinity and put a square around the element with the lowest electron affinity: Cu K Ni Br Highest – Br
Smallest - K Explain why you made these choices. Electron affinity increases as you go left to right across a period. Potassium is in the
far left group of period 4, and bromine is the farthest to the right of the four elements. 4. Circle the element with the highest electronegativity and put a square around the element with the lowest electronegativity: Cu K Ni Br Highest – Br
Smallest - K Explain why you made these choices. Electronegativity increases as you go left to right across a period. Potassium is in the
far left group of period 4, and bromine is the farthest to the right of the four elements. 5. Circle the element with the largest atomic radius and put a square around the element with the smallest atomic radius: O C Be Ne Largest – Be
Smallest - Ne Explain why you made these choices. Atomic radius decreases as you go left to right across a period. Beryllium is in the
farthest to the left, and neon is the farthest to the right of the four elements. 6. Circle the element with the highest ionization energy and put a square around the element with the lowest ionization energy: O C Be Ne Highest – Ne
Smallest - Be Explain why you made these choices. Ionization energy increases as you go left to right across a period. Beryllium is in the
farthest to the left, and neon is the farthest to the right of the four elements. 7. Circle the element with the highest electron affinity and put a square around the element with the lowest electron affinity: O C Be Ne Highest – Ne
Smallest - Be Explain why you made these choices. Electron affinity increases as you go left to right across a period. Beryllium is in the
farthest to the left, and neon is the farthest to the right of the four elements. 8. Circle the element with the highest electronegativity and put a square around the element with the lowest electronegativity: O C Be Ne Highest – O
Smallest - Be Explain why you made these choices. Electronegativity increases as you go left to right across a period, stopping at group 17.
Noble gases do not have electronegativity. Beryllium is in the farthest to the left, and
oxygen is the farthest to the right of the three elements, excluding neon. If you picked
neon based on the general trend, that’s okay! 9. Circle the element with the largest atomic radius and put a square around the element with the smallest atomic radius: Na Rb Fr H Largest – Fr
Smallest - H Explain why you made these choices. Atomic radius increases as you go down a group. All four elements are in group 1.
Francium is at the bottom of group 1, and hydrogen is the closest to the top.
10. Circle the element with the highest ionization energy and put a square around the element with the lowest ionization energy: Na Rb Fr H Highest – H Lowest - Fr Explain why you made these choices. Ionization energy decreases as you go down a group. All four elements are in group 1.
Francium as at the bottom of group 1, and hydrogen is the closest to the top.
11. Circle the element with the highest electron affinity and put a square around the element with the lowest electron affinity: Na Rb Fr H Highest – H
Lowest - Fr Explain why you made these choices. Electron affinity decreases as you go down a group. All four elements are in group 1.
Francium as at the bottom of group 1, and hydrogen is the closest to the top. 12. Circle the element with the highest electronegativity and put a square around the element with the lowest electronegativity: Na Rb Fr H Highest – H Lowest - Fr Explain why you made these choices. Electronegativity decreases as you go down a group. All four elements are in group 1.
Francium as at the bottom of group 1, and hydrogen is the closest to the top. 13. Circle the element with the largest atomic radius and put a square around the element with the smallest atomic radius: Pb C Sn Si Largest – Pb
Smallest - C Explain why you made these choices. Atomic radius increases as you go down a group. All four elements are in group 14. Lead
is toward the bottom of the group, and carbon is at the top of the group. 14. Circle the element with the highest ionization energy and put a square around the element with the lowest ionization energy: Pb C Sn Si Highest – C
Lowest - Pb Explain why you made these choices. Ionization energy decreases as you go down a group. All four elements are in group 14.
Lead is toward the bottom of the group, and carbon is at the top of the group. 15. Circle the element with the highest electron affinity and put a square around the element with the lowest electron affinity: Pb C Sn Si Highest – C
Lowest - Pb Explain why you made these choices. Electron affinity decreases as you go down a group. All four elements are in group 14.
Lead is toward the bottom of the group, and carbon is at the top of the group. 16. Circle the element with the highest electronegativity and put a square around the element with the lowest electronegativity: Pb C Sn Si Highest – C
Lowest - Pb Explain why you made these choices. Electronegativity decreases as you go down a group. All four elements are in group 14.
Lead is toward the bottom of the group, and carbon is at the top of the group. 17. Circle the element with the largest atomic radius and put a square around the element with the smallest atomic radius: Au W S Fr Ne Zn Largest – Fr
Smallest - Ne Explain why you made these choices. Atomic radius decreases as you move up a group and to the right in a period. Francium is
at the bottom of the far-left group; while neon is on the far-right of the 2nd period.
18. Circle the element with the highest ionization energy and put a square around the element with the lowest ionization energy: Highest – Ne
Au W S Fr Ne Zn Lowest - Fr Explain why you made these choices. Ionization energy increases as you move up a group and to the right in a period. Francium
is at the bottom of the far-left group; while neon is on the far-right of the 2nd period. 19. Circle the element with the highest electron affinity and put a square around the element with the lowest electron affinity: Au W S Fr Ne Zn Highest – Ne
Lowest - Fr Explain why you made these choices. Electron affinity increases as you move up a group and to the right in a period. Francium
is at the bottom of the far-left group; while neon is on the far-right of the 2nd period. 20. Circle the element with the highest electronegativity and put a square around the element with the lowest electronegativity: Highest – Ne
Au W S Fr Ne Zn Lowest - Fr Explain why you made these choices. Electronegativity increases as you move up a group and to the right in a period. Francium
is at the bottom of the far-left group; while neon is on the far-right of the 2nd period. 21. Circle the ions that will have a larger radius than the radius of their neutral atom. Put a square around the ions that will have a smaller radius than the radius of their neutral atom. Na+ Sr2+ P3-­‐ Cr3+ O2-­‐ C4-­‐ C4+ Ag+ Br-­‐ Explain why you made these choices. Cations will be smaller than their neutral atom. These positively charged ions have lost
electrons compared to their neutral atom. There is less electron-electron repulsion than
in the neutral atom, which allows the nucleus to pull the outer electrons in even closer.
Anions will be smaller than their neutral atom. These negatively charged ions have gained
electrons compared to their neutral atom. There is more electron-electron repulsion
than in the neutral atom, which doesn’t allow the nucleus to pull the electrons as close
as in the neutral atom.
22. Circle the ion in each set below that will have a largest radius. If there are more than two ions in a set, put a square around the ion that will have the smallest radius in the set. Explain why you made these choices. a. Cu+ Cu2+ Largest – Cu+ b. Cr3+ Cr2+ Cr6+ Cr4+ Largest – Cr2+
Smallest – Cr6+ c.
Cl7+ Cl5+ Cl3+ Largest – Cl1-
Smallest – Cl7+ O1-­‐ Largest – O2- Cl-­‐ d. O2-­‐ For cations of the same element, the one with the largest charge will have the
smallest radius, and the one with the smallest charge will have the largest radius.
For anions of the same element, the one with the largest negative charge will have the
largest radius and the one with the smallest negative charge will have the smallest
radius.