MCAT Chemical and Physical Foundations of Biological Systems Flashcards: 4e Periodic Trends Atomic Properties

What this deck covers

This deck focuses on 4e Periodic Trends Atomic Properties, giving you a quick way to review the definitions, rules, and examples that matter most for MCAT Chemical and Physical Foundations of Biological Systems.

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Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the periodic trend for electron affinity (more negative) when moving left to right across a period?

Answer: Electron affinity becomes more negative across a period. Smaller radius and higher $Z_{\mathrm{eff}}$ stabilize added electron more effectively.

Flashcard 2: Which has the larger radius: Na or Na$^+$?

Answer: Na has the larger radius. Neutral Na has one more electron than Na$^+$, increasing repulsion and size.

Flashcard 3: Which has the larger radius: Cl or Cl$^-$?

Answer: Cl$^-$ has the larger radius. Cl$^-$ has an extra electron, causing greater repulsion and larger size than neutral Cl.

Flashcard 4: What is the periodic trend for atomic radius when moving left to right across a period?

Answer: Atomic radius decreases across a period (left to right). Increasing effective nuclear charge pulls electrons closer without adding new shells.

Flashcard 5: What is the periodic trend for electron affinity (more negative) when moving down a group in the periodic table?

Answer: Electron affinity becomes less negative down a group. Increased size weakens nuclear attraction, making electron addition less exothermic.

Flashcard 6: What is the periodic trend for first ionization energy when moving left to right across a period?

Answer: First ionization energy increases across a period. Higher $Z_{\mathrm{eff}}$ and smaller radius make it harder to remove an electron.

Flashcard 7: What is the periodic trend for electronegativity when moving left to right across a period?

Answer: Electronegativity increases across a period. Increasing $Z_{\mathrm{eff}}$ enhances attraction for shared electrons in bonds.

Flashcard 8: Which has the larger atomic radius: Na or Cl (both in period $3$)?

Answer: Na has the larger atomic radius. Na experiences lower $Z_{\mathrm{eff}}$ than Cl due to position earlier in the period.

Flashcard 9: What is the periodic trend for first ionization energy when moving down a group in the periodic table?

Answer: First ionization energy decreases down a group. Larger atomic radius reduces nuclear attraction on valence electrons, easing removal.

Flashcard 10: Which has the more negative electron affinity: Cl or Ar (same period $3$)?

Answer: Cl has the more negative electron affinity. Cl, as a halogen, readily accepts an electron to complete octet, unlike noble gas Ar.

Flashcard 11: For an isoelectronic series, what is the trend in ionic radius as nuclear charge $Z$ increases?

Answer: Ionic radius decreases as $Z$ increases (isoelectronic series). Higher nuclear charge compresses the same electron configuration more effectively.

Flashcard 12: What is the periodic trend for electronegativity when moving down a group in the periodic table?

Answer: Electronegativity decreases down a group. Larger size diminishes nuclear pull on valence electrons, reducing attraction in bonds.

Flashcard 13: What is the periodic trend for metallic character when moving left to right across a period?

Answer: Metallic character decreases across a period. Higher electronegativity and nonmetallic nature reduce tendency to lose electrons.

Flashcard 14: Which has the higher first ionization energy: Mg or Al (both in period $3$)?

Answer: Mg has the higher first ionization energy. Mg's full 3s subshell is more stable than Al's 3p electron, requiring more energy to ionize.

Flashcard 15: What is the periodic trend for reactivity of alkali metals (group $1$) when moving down the group?

Answer: Alkali metal reactivity increases down the group. Decreasing ionization energy down the group eases electron loss in reactions.

Flashcard 16: What is the periodic trend for atomic radius when moving down a group in the periodic table?

Answer: Atomic radius increases down a group. Addition of new electron shells increases distance from nucleus, outweighing higher $Z_{\mathrm{eff}}$.

Flashcard 17: What is the relationship between $Z_{\mathrm{eff}}$ and atomic radius for atoms in the same period?

Answer: Higher $Z_{\mathrm{eff}}$ corresponds to smaller atomic radius. Stronger nuclear pull contracts electron cloud in atoms with similar electron count.

Flashcard 18: What is the periodic trend for metallic character when moving down a group in the periodic table?

Answer: Metallic character increases down a group. Lower ionization energy facilitates easier loss of electrons for metallic reactions.

Flashcard 19: Which has the larger atomic radius: K or Na (both in group $1$)?

Answer: K has the larger atomic radius. K has an additional electron shell compared to Na, increasing overall size.

Flashcard 20: Which has the higher electronegativity: F or Cl (same group, different periods)?

Answer: F has the higher electronegativity. Smaller size of F increases its ability to attract bonding electrons compared to Cl.

Flashcard 21: What happens to atomic radius when an atom forms a cation compared with the neutral atom?

Answer: Radius decreases when a cation forms. Loss of electrons reduces electron-electron repulsion, allowing tighter nuclear pull.

Flashcard 22: What happens to atomic radius when an atom forms an anion compared with the neutral atom?

Answer: Radius increases when an anion forms. Gain of electrons increases repulsion, expanding the electron cloud.

Flashcard 23: Which has the smallest radius in the isoelectronic set: O$^{2-}$, F$^-$, Ne, Na$^+$, Mg$^{2+}$?

Answer: Mg$^{2+}$ has the smallest radius. Mg$^{2+}$ has the highest nuclear charge, pulling electrons closest in the series.

Flashcard 24: What is the effective nuclear charge $Z_{\mathrm{eff}}$ in terms of $Z$ and shielding $S$?

Answer: $Z_{\mathrm{eff}}=Z-S$. Effective nuclear charge accounts for protons minus shielding by inner electrons.

Flashcard 25: Which has the higher first ionization energy: N or O (both in period $2$)?

Answer: N has the higher first ionization energy. N's half-filled p subshell provides extra stability compared to O's paired electrons.