Trends in ionization energy and atomic radius across the periodic table.
Graph showing ionization energy and atomic radius trends across the periodic table, with data points for elements H to Ca.
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Step-by-step solution for: Trends in the Periodic Table Worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Trends in the Periodic Table Worksheet
1) Plot ionization energy (y-axis) vs. atomic number (x-axis) on the top half; plot atomic radius (y-axis) vs. atomic number (x-axis) on the bottom half. Connect successive data points with straight lines. Align identical atomic numbers vertically across both graphs.
2) a) Peaks occur at He, Ne, Ar — noble gases. They have full valence shells, making them exceptionally stable and requiring high energy to remove an electron.
b) Valleys occur at Li, Na, K — alkali metals. They have a single valence electron, which is easily removed due to low effective nuclear charge and large atomic size.
3) a) Peaks occur at He, Ne, Ar — noble gases. They have complete valence shells and minimal electron-electron repulsion relative to nuclear pull, resulting in smaller radii for their periods.
b) Valleys occur at Li, Na, K — alkali metals. They have the largest atomic radii in their respective periods due to having only one valence electron and the lowest effective nuclear charge felt by that outermost electron.
4) As atomic radius increases, ionization energy decreases. A larger radius means the outermost electrons are farther from the nucleus, experiencing weaker electrostatic attraction, so less energy is required to remove them.
5) Moving left to right across a period, atomic radius decreases due to increasing nuclear charge pulling electrons closer; ionization energy increases because electrons are held more tightly.
6) Moving down a group, atomic radius increases due to addition of electron shells; ionization energy decreases because outer electrons are farther from the nucleus and shielded by inner electrons.
7) Na: 1s² 2s² 2p⁶ 3s¹ → Na⁺: 1s² 2s² 2p⁶. Na⁺ resembles Ne (same electron configuration). Alkali metals resemble noble gases when they lose their outer electron.
8) Radius increases down a group because each successive element adds a new principal energy level (shell), increasing distance from nucleus. Larger radius makes losing an outer electron easier (lower ionization energy) because the electron is less strongly attracted to the nucleus.
9) Proton number increases across a period. More protons increase nuclear charge, pulling electrons closer (decreasing radius) and increasing the energy needed to remove an electron (increasing ionization energy).
10) The noble gas group (Group 18) is often ignored in trend discussions because they have very high ionization energies and nearly zero electron affinity, making them chemically inert and outliers in reactivity trends.
11) Electron affinity is the energy change when an atom gains an electron. It is highest in the upper right corner (excluding noble gases), particularly at fluorine or chlorine, because small atoms with high effective nuclear charge strongly attract additional electrons.
12) Electronegativity is an atom’s ability to attract shared electrons in a bond. It is highest in the upper right corner (fluorine), because small atomic size and high nuclear charge allow the atom to strongly attract bonding electrons.
2) a) Peaks occur at He, Ne, Ar — noble gases. They have full valence shells, making them exceptionally stable and requiring high energy to remove an electron.
b) Valleys occur at Li, Na, K — alkali metals. They have a single valence electron, which is easily removed due to low effective nuclear charge and large atomic size.
3) a) Peaks occur at He, Ne, Ar — noble gases. They have complete valence shells and minimal electron-electron repulsion relative to nuclear pull, resulting in smaller radii for their periods.
b) Valleys occur at Li, Na, K — alkali metals. They have the largest atomic radii in their respective periods due to having only one valence electron and the lowest effective nuclear charge felt by that outermost electron.
4) As atomic radius increases, ionization energy decreases. A larger radius means the outermost electrons are farther from the nucleus, experiencing weaker electrostatic attraction, so less energy is required to remove them.
5) Moving left to right across a period, atomic radius decreases due to increasing nuclear charge pulling electrons closer; ionization energy increases because electrons are held more tightly.
6) Moving down a group, atomic radius increases due to addition of electron shells; ionization energy decreases because outer electrons are farther from the nucleus and shielded by inner electrons.
7) Na: 1s² 2s² 2p⁶ 3s¹ → Na⁺: 1s² 2s² 2p⁶. Na⁺ resembles Ne (same electron configuration). Alkali metals resemble noble gases when they lose their outer electron.
8) Radius increases down a group because each successive element adds a new principal energy level (shell), increasing distance from nucleus. Larger radius makes losing an outer electron easier (lower ionization energy) because the electron is less strongly attracted to the nucleus.
9) Proton number increases across a period. More protons increase nuclear charge, pulling electrons closer (decreasing radius) and increasing the energy needed to remove an electron (increasing ionization energy).
10) The noble gas group (Group 18) is often ignored in trend discussions because they have very high ionization energies and nearly zero electron affinity, making them chemically inert and outliers in reactivity trends.
11) Electron affinity is the energy change when an atom gains an electron. It is highest in the upper right corner (excluding noble gases), particularly at fluorine or chlorine, because small atoms with high effective nuclear charge strongly attract additional electrons.
12) Electronegativity is an atom’s ability to attract shared electrons in a bond. It is highest in the upper right corner (fluorine), because small atomic size and high nuclear charge allow the atom to strongly attract bonding electrons.
Parent Tip: Review the logic above to help your child master the concept of trends in the periodic table worksheet answers.
