Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity

Cards in this deck

1. Card 1

   Question

   What is a periodic trend?

   Answer

   A recurring pattern in element properties as atomic number increases across periods and down groups.

2. Card 2

   Question

   What does covalent radius measure?

   Answer

   Half the distance between the nuclei of two identical atoms joined by a covalent bond.

3. Card 3

   Question

   What is first ionization energy?

   Answer

   The minimum energy needed to remove the most loosely bound electron from an isolated gaseous atom in its ground state.

4. Card 4

   Question

   What is electronegativity?

   Answer

   An atom's ability to attract shared electrons toward itself in a chemical bond.

5. Card 5

   Question

   What is a period on the periodic table?

   Answer

   A horizontal row. For main-group elements, moving across a period fills orbitals in the same principal electron shell.

6. Card 6

   Question

   What is ionic radius?

   Answer

   A measure of an ion's size, usually inferred from distances between ions in crystals.

7. Card 7

   Question

   What does electron affinity describe?

   Answer

   The energy change when an electron is added to an isolated gaseous atom to form a gaseous anion.

8. Card 8

   Question

   What does metallic character describe?

   Answer

   How readily an element shows metallic behavior, especially losing valence electrons and forming cations.

9. Card 9

   Question

   What is a group on the periodic table?

   Answer

   A vertical column. Main-group elements in one group usually share a valence-electron pattern and similar chemistry.

10. Card 10

    Question

    What is effective nuclear charge?

    Answer

    The net positive pull an electron feels from the nucleus after shielding and electron–electron repulsion are taken into account.

11. Card 11

    Question

    What are successive ionization energies?

    Answer

    The energies needed to remove electrons one after another from the same atom, then from its increasingly positive ions.

12. Card 12

    Question

    How does electronegativity difference relate to bond polarity?

    Answer

    A larger difference generally produces a more uneven electron distribution and a more polar bond.

13. Card 13

    Question

    Why do main-group elements in one group often behave similarly?

    Answer

    They have the same general number and arrangement of valence electrons, which drive much of their bonding and reactivity.

14. Card 14

    Question

    What is electron shielding?

    Answer

    The reduction in nuclear attraction felt by an electron because other electrons lie between it and the nucleus and repel it.

15. Card 15

    Question

    Why does the definition of ionization energy specify a gaseous atom?

    Answer

    It isolates the atom from bonding and intermolecular effects, so the energy reflects electron removal from that species itself.

16. Card 16

    Question

    Where are metals and nonmetals generally found on the periodic table?

    Answer

    Metals occupy the left and center; nonmetals cluster toward the upper right, with metalloids near the boundary.

17. Card 17

    Question

    What changes in the electron arrangement across a main-group period?

    Answer

    Electrons are added to the same principal shell while the nucleus gains one proton from one element to the next.

18. Card 18

    Question

    How does atomic radius generally change from left to right across a period?

    Answer

    It decreases.

19. Card 19

    Question

    How does first ionization energy generally change from left to right across a period?

    Answer

    It increases, although a few recurring subshell and electron-pairing exceptions interrupt the rise.

20. Card 20

    Question

    How does electronegativity generally change from left to right across a period?

    Answer

    It increases for the elements normally assigned electronegativity values.

21. Card 21

    Question

    What changes in the electron arrangement down a main-group group?

    Answer

    Each step adds a higher principal electron shell while preserving a similar valence-electron pattern.

22. Card 22

    Question

    How does atomic radius generally change down a group?

    Answer

    It increases.

23. Card 23

    Question

    How does first ionization energy generally change down a group?

    Answer

    It decreases.

24. Card 24

    Question

    How does electronegativity generally change down a group?

    Answer

    It decreases.

25. Card 25

    Question

    How does effective nuclear charge generally change across a main-group period?

    Answer

    It increases because nuclear charge rises while added electrons enter the same principal shell and do not fully shield one another.

26. Card 26

    Question

    How does a cation's radius compare with its neutral parent atom?

    Answer

    The cation is smaller.

27. Card 27

    Question

    How does electron addition generally change across a period?

    Answer

    It generally becomes more energetically favorable toward the right, but electron affinity has substantial exceptions and depends on the sign convention used.

28. Card 28

    Question

    How does metallic character generally change from left to right across a period?

    Answer

    It decreases.

29. Card 29

    Question

    Why are valence electrons generally farther from the nucleus down a group?

    Answer

    They occupy shells with higher principal quantum numbers, so the electron cloud extends farther outward.

30. Card 30

    Question

    How does an anion's radius compare with its neutral parent atom?

    Answer

    The anion is larger.

31. Card 31

    Question

    How does favorable electron addition generally change down a group?

    Answer

    It generally becomes less favorable as the added electron enters a larger, more shielded shell, though electron-affinity irregularities are common.

32. Card 32

    Question

    How does metallic character generally change down a group?

    Answer

    It increases.

33. Card 33

    Question

    Why does shielding change less than nuclear charge across a main-group period?

    Answer

    The added electrons enter the same principal shell, so they do not shield one another as effectively as inner-shell electrons do.

34. Card 34

    Question

    Which has the larger atomic radius, Li or Na?

    Answer

    Na. It lies below Li and has an additional occupied electron shell.

35. Card 35

    Question

    Which has the larger atomic radius, Na or Mg?

    Answer

    Na. Atomic radius generally decreases from left to right across Period 3.

36. Card 36

    Question

    How does greater electron–nucleus distance affect electrostatic attraction?

    Answer

    It weakens the attraction, all else being equal.

37. Card 37

    Question

    How do successive ionization energies for one element compare?

    Answer

    Each successive ionization energy is higher than the one before it because an electron is removed from an increasingly positive species.

38. Card 38

    Question

    Which has the higher first ionization energy, Li or Na?

    Answer

    Li. Its valence electron is closer to the nucleus and less shielded.

39. Card 39

    Question

    Which has the higher first ionization energy, Na or Mg?

    Answer

    Mg. Its greater effective nuclear charge holds the valence electrons more tightly.

40. Card 40

    Question

    Why does forming a cation usually shrink an atom?

    Answer

    Electron loss reduces electron–electron repulsion and increases the nuclear pull per remaining electron; losing the outer shell can shrink it sharply.

41. Card 41

    Question

    Which element is most electronegative on the Pauling scale?

    Answer

    Fluorine.

42. Card 42

    Question

    Which is more electronegative, Li or Na?

    Answer

    Li. Electronegativity generally decreases down Group 1.

43. Card 43

    Question

    Which is more electronegative, Na or Mg?

    Answer

    Mg. Electronegativity generally increases across Period 3.

44. Card 44

    Question

    What does a large jump between successive ionization energies reveal?

    Answer

    The next electron would come from a lower, core shell; the number removed before the jump indicates the valence-electron count for a main-group atom.

45. Card 45

    Question

    Why is Cl⁻ larger than neutral Cl?

    Answer

    The added electron increases repulsion within the valence shell while the nuclear charge stays the same.

46. Card 46

    Question

    How do you compare the radii of isoelectronic species?

    Answer

    The species with more protons is smaller because the same number of electrons feels a stronger nuclear attraction.

47. Card 47

    Question

    Why does an atom have no single sharp physical radius?

    Answer

    Its electron cloud has no hard edge, so atomic size depends on a defined measurement such as covalent, metallic, or van der Waals radius.

48. Card 48

    Question

    Why are noble-gas electronegativities often omitted in introductory tables?

    Answer

    Electronegativity describes attraction in a bond, and many noble gases form too few ordinary bonds for a standard value to be useful on common scales.

49. Card 49

    Question

    Why does forming an anion usually expand an atom?

    Answer

    The extra electron increases electron–electron repulsion and lowers the nuclear pull available per electron.

50. Card 50

    Question

    Order O²⁻, F⁻, and Ne from largest to smallest radius.

    Answer

    O²⁻ > F⁻ > Ne. All have 10 electrons, and increasing proton count pulls that electron cloud inward.

51. Card 51

    Question

    After which removal does Na show its first large ionization-energy jump?

    Answer

    After the first electron. Removing one valence electron leaves a stable core, so the second removal reaches that core.

52. Card 52

    Question

    Does electronegativity difference create a universal ionic-versus-covalent cutoff?

    Answer

    No. A larger difference usually means more bond polarity, but bonding lies on a continuum and context matters.

53. Card 53

    Question

    How do noble gases generally differ from halogens in electron affinity?

    Answer

    Adding an electron to a noble gas is generally unfavorable because it must begin a higher-energy shell; halogens usually gain one much more favorably.

54. Card 54

    Question

    Which is smaller, Na⁺ or Mg²⁺?

    Answer

    Mg²⁺. Both have 10 electrons, but Mg²⁺ has one more proton.

55. Card 55

    Question

    After which removal does Mg show its first large ionization-energy jump?

    Answer

    After the second electron. Mg has two valence electrons, so the third removal reaches a core shell.

56. Card 56

    Question

    How does electronegativity differ from electron affinity?

    Answer

    Electronegativity is a relative measure of attraction for shared electrons in a bond; electron affinity is an energy change for adding an electron to an isolated gaseous species.

57. Card 57

    Question

    How are atomic radius and first ionization energy generally related?

    Answer

    A larger radius usually means a lower first ionization energy because the valence electron is farther from the nucleus and easier to remove.

58. Card 58

    Question

    Which has the more exothermic first electron affinity, F or Cl?

    Answer

    Cl. Fluorine's very compact 2p shell creates stronger electron–electron repulsion for the incoming electron, so this pair breaks the simple down-group expectation.

59. Card 59

    Question

    Which has the higher first ionization energy, Be or B?

    Answer

    Be. B loses a higher-energy 2p electron, while Be loses a more penetrating 2s electron from a filled 2s subshell.

60. Card 60

    Question

    Why does Group 1 metal reactivity generally increase down the group?

    Answer

    The valence electron is farther out and more shielded, so its first ionization energy falls and electron loss becomes easier.

61. Card 61

    Question

    How are atomic radius and electronegativity generally related?

    Answer

    Smaller atoms usually attract bonding electrons more strongly, so electronegativity tends to rise as radius falls.

62. Card 62

    Question

    Why is Na⁺ much smaller than neutral Na?

    Answer

    Na loses its entire third-shell valence level, leaving the smaller neon-like electron configuration.

63. Card 63

    Question

    Which has the higher first ionization energy, Mg or Al?

    Answer

    Mg. Al's removed electron is a higher-energy 3p electron, while Mg loses a more penetrating 3s electron from a filled 3s subshell.

64. Card 64

    Question

    Why does halogen reactivity generally decrease down Group 17?

    Answer

    Larger radius and greater shielding weaken attraction for an incoming electron, so oxidizing ability generally falls. Particular reactions still depend on bond energies and conditions.

65. Card 65

    Question

    Why do Groups 2 and 15 often interrupt the simple electron-affinity trend?

    Answer

    Group 2 has a filled s subshell and Group 15 has a half-filled p subshell, so an added electron enters a less favorable arrangement.

66. Card 66

    Question

    Can ion charge alone rank two unrelated ionic radii?

    Answer

    No. Shell number, electron count, proton count, oxidation state, and crystal environment can all matter; the isoelectronic rule needs the same electron count.

67. Card 67

    Question

    Which has the higher first ionization energy, N or O?

    Answer

    N. Its half-filled 2p subshell is relatively stable; O has one paired 2p orbital, and repulsion makes one electron easier to remove.

68. Card 68

    Question

    In which direction does nonmetallic character generally increase?

    Answer

    Up and to the right, opposite the general trend in metallic character.

69. Card 69

    Question

    Within the same principal shell, which penetrates closer to the nucleus: an s or p orbital?

    Answer

    An s orbital. Greater penetration means its electrons are less shielded and usually lower in energy than p electrons in the same shell.

70. Card 70

    Question

    How do same-charge ion radii generally change down a group?

    Answer

    They increase as occupied electron shells are added.

71. Card 71

    Question

    Which has the higher first ionization energy, P or S?

    Answer

    P. Its half-filled 3p subshell is relatively stable; S contains a paired 3p orbital that increases repulsion and eases removal.

72. Card 72

    Question

    Why should simple periodic-direction rules be used cautiously for transition metals?

    Answer

    d-electron filling, shielding, oxidation state, and contraction effects make their property changes less regular than main-group trends.

73. Card 73

    Question

    Why do periodic-trend statements usually say “generally”?

    Answer

    Subshell energies, electron pairing, radius definitions, and element-specific configurations create real exceptions to the broad patterns.

74. Card 74

    Question

    Which has the larger atomic radius, K or Br?

    Answer

    K. Both are in Period 4, and atomic radius generally decreases from left to right.

75. Card 75

    Question

    Which has the higher first ionization energy, Mg or Cl?

    Answer

    Cl. Its valence electrons experience greater effective nuclear charge and are held more tightly.

76. Card 76

    Question

    Which is more electronegative, Al or Si?

    Answer

    Si. Electronegativity generally increases across Period 3.

77. Card 77

    Question

    Which has the larger atomic radius, O or F?

    Answer

    O. Atomic radius generally decreases across Period 2.

78. Card 78

    Question

    Which has the higher first ionization energy, K or Br?

    Answer

    Br. First ionization energy generally increases across Period 4.

79. Card 79

    Question

    Which is more electronegative, Mg or Cl?

    Answer

    Cl. It lies farther right in Period 3.

80. Card 80

    Question

    Which has the larger atomic radius, Al or Si?

    Answer

    Al. Atomic radius generally decreases across Period 3 as effective nuclear charge rises.

81. Card 81

    Question

    Which has the higher first ionization energy, O or F?

    Answer

    F. This pair follows the general increase across Period 2.

82. Card 82

    Question

    Which is more electronegative, K or Br?

    Answer

    Br. Electronegativity generally increases across Period 4.

83. Card 83

    Question

    Which has the larger atomic radius, Mg or Cl?

    Answer

    Mg. Both are in Period 3, and Mg lies farther left.

84. Card 84

    Question

    Which has the higher first ionization energy, Al or Si?

    Answer

    Si. This pair follows the general increase across Period 3.

85. Card 85

    Question

    Which is more electronegative, O or F?

    Answer

    F, the most electronegative element on the Pauling scale.

86. Card 86

    Question

    Order Al³⁺, Mg²⁺, Na⁺, Ne, F⁻, and O²⁻ from smallest to largest radius.

    Answer

    Al³⁺ < Mg²⁺ < Na⁺ < Ne < F⁻ < O²⁻. All have 10 electrons, so radius grows as proton count falls.

87. Card 87

    Question

    Why do upper-right nonmetals usually hold valence electrons tightly?

    Answer

    Their relatively small radii and high effective nuclear charges create strong attraction between the nucleus and valence electrons.

88. Card 88

    Question

    Across a main-group period, what shared cause links smaller radius, higher ionization energy, and higher electronegativity?

    Answer

    Increasing effective nuclear charge pulls the same-shell valence electrons inward and holds them more strongly.

88 cards

Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity

Study this deck for free

Flashcards opens so you can start studying.