Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
Review 88 concise cards on atomic and ionic radius, shielding, effective nuclear charge, ionization energy, electron affinity, electronegativity, metallic character, exceptions, and comparisons.
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Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
Study the core periodic trends with 88 independently written English flashcards for high-school and introductory-college chemistry. The deck separates broad patterns from the reasons behind them and uses generally where real configurations create exceptions.
What the cards practice
The sequence covers four useful recall paths: term to definition; table movement to a general property direction; cause to effect through shell number, shielding, distance, and effective nuclear charge; and a concrete pair or isoelectronic set to the expected comparison. Atomic and ionic radius, first and successive ionization energies, electron affinity, electronegativity, metallic character, and selected reactivity links are all included.
The course-level exceptions are deliberately small: Be versus B, Mg versus Al, N versus O, P versus S, and Cl versus F electron affinity. Electron-affinity wording distinguishes a favorable electron gain from the sign convention used by a source. Electronegativity stays tied to bonded atoms, and ionic-radius comparisons state when an isoelectronic rule applies.
Learning order
Definitions and table structure come first. General directions follow, then causal models, ion-size rules, successive-ionization reasoning, limited exceptions, and applied comparisons. Related prompts are spaced apart in a fixed order; the review scheduler handles longer-term interleaving after installation.
Scope
This deck teaches qualitative periodic-trend reasoning. It excludes exact numerical property tables, memorizing values for all 118 elements, advanced transition-metal irregularities, diagonal relationships, melting and boiling trends, broad group trivia, and copied examination or competitor material. It supports chemistry practice but does not replace calculation, laboratory, or full-course problem solving.
Sources and license
Core trends and explanations were checked against OpenStax Chemistry: Atoms First 2e, section 3.5 and its electronegativity discussion in section 4.2. Terminology was cross-checked against the IUPAC Gold Book entries for ionization energy, electron affinity, and electronegativity.
The prompts, answers, examples, organization, metadata, and generated cover were created independently from common chemistry knowledge and original work. No protected cards, textbook prose, source figures, exact property tables, logos, or third-party media were copied.
The Common knowledge · CC0 1.0 label applies only to the original prompts, answers, examples, organization, metadata, and cover, to the extent applicable rights exist. It does not claim ownership of scientific facts or third-party material.
Source review date: August 29, 2026.
Kartu dalam dek ini
Kartu 1
Pertanyaan
What is a periodic trend?
Jawaban
A recurring pattern in element properties as atomic number increases across periods and down groups.
Kartu 2
Pertanyaan
What does covalent radius measure?
Jawaban
Half the distance between the nuclei of two identical atoms joined by a covalent bond.
Kartu 3
Pertanyaan
What is first ionization energy?
Jawaban
The minimum energy needed to remove the most loosely bound electron from an isolated gaseous atom in its ground state.
Kartu 4
Pertanyaan
What is electronegativity?
Jawaban
An atom's ability to attract shared electrons toward itself in a chemical bond.
Kartu 5
Pertanyaan
What is a period on the periodic table?
Jawaban
A horizontal row. For main-group elements, moving across a period fills orbitals in the same principal electron shell.
Kartu 6
Pertanyaan
What is ionic radius?
Jawaban
A measure of an ion's size, usually inferred from distances between ions in crystals.
Kartu 7
Pertanyaan
What does electron affinity describe?
Jawaban
The energy change when an electron is added to an isolated gaseous atom to form a gaseous anion.
Kartu 8
Pertanyaan
What does metallic character describe?
Jawaban
How readily an element shows metallic behavior, especially losing valence electrons and forming cations.
Kartu 9
Pertanyaan
What is a group on the periodic table?
Jawaban
A vertical column. Main-group elements in one group usually share a valence-electron pattern and similar chemistry.
Kartu 10
Pertanyaan
What is effective nuclear charge?
Jawaban
The net positive pull an electron feels from the nucleus after shielding and electron–electron repulsion are taken into account.
Kartu 11
Pertanyaan
What are successive ionization energies?
Jawaban
The energies needed to remove electrons one after another from the same atom, then from its increasingly positive ions.
Kartu 12
Pertanyaan
How does electronegativity difference relate to bond polarity?
Jawaban
A larger difference generally produces a more uneven electron distribution and a more polar bond.
Kartu 13
Pertanyaan
Why do main-group elements in one group often behave similarly?
Jawaban
They have the same general number and arrangement of valence electrons, which drive much of their bonding and reactivity.
Kartu 14
Pertanyaan
What is electron shielding?
Jawaban
The reduction in nuclear attraction felt by an electron because other electrons lie between it and the nucleus and repel it.
Kartu 15
Pertanyaan
Why does the definition of ionization energy specify a gaseous atom?
Jawaban
It isolates the atom from bonding and intermolecular effects, so the energy reflects electron removal from that species itself.
Kartu 16
Pertanyaan
Where are metals and nonmetals generally found on the periodic table?
Jawaban
Metals occupy the left and center; nonmetals cluster toward the upper right, with metalloids near the boundary.
Kartu 17
Pertanyaan
What changes in the electron arrangement across a main-group period?
Jawaban
Electrons are added to the same principal shell while the nucleus gains one proton from one element to the next.
Kartu 18
Pertanyaan
How does atomic radius generally change from left to right across a period?
Jawaban
It decreases.
Kartu 19
Pertanyaan
How does first ionization energy generally change from left to right across a period?
Jawaban
It increases, although a few recurring subshell and electron-pairing exceptions interrupt the rise.
Kartu 20
Pertanyaan
How does electronegativity generally change from left to right across a period?
Jawaban
It increases for the elements normally assigned electronegativity values.
Kartu 21
Pertanyaan
What changes in the electron arrangement down a main-group group?
Jawaban
Each step adds a higher principal electron shell while preserving a similar valence-electron pattern.
Kartu 22
Pertanyaan
How does atomic radius generally change down a group?
Jawaban
It increases.
Kartu 23
Pertanyaan
How does first ionization energy generally change down a group?
Jawaban
It decreases.
Kartu 24
Pertanyaan
How does electronegativity generally change down a group?
Jawaban
It decreases.
Kartu 25
Pertanyaan
How does effective nuclear charge generally change across a main-group period?
Jawaban
It increases because nuclear charge rises while added electrons enter the same principal shell and do not fully shield one another.
Kartu 26
Pertanyaan
How does a cation's radius compare with its neutral parent atom?
Jawaban
The cation is smaller.
Kartu 27
Pertanyaan
How does electron addition generally change across a period?
Jawaban
It generally becomes more energetically favorable toward the right, but electron affinity has substantial exceptions and depends on the sign convention used.
Kartu 28
Pertanyaan
How does metallic character generally change from left to right across a period?
Jawaban
It decreases.
Kartu 29
Pertanyaan
Why are valence electrons generally farther from the nucleus down a group?
Jawaban
They occupy shells with higher principal quantum numbers, so the electron cloud extends farther outward.
Kartu 30
Pertanyaan
How does an anion's radius compare with its neutral parent atom?
Jawaban
The anion is larger.
Kartu 31
Pertanyaan
How does favorable electron addition generally change down a group?
Jawaban
It generally becomes less favorable as the added electron enters a larger, more shielded shell, though electron-affinity irregularities are common.
Kartu 32
Pertanyaan
How does metallic character generally change down a group?
Jawaban
It increases.
Kartu 33
Pertanyaan
Why does shielding change less than nuclear charge across a main-group period?
Jawaban
The added electrons enter the same principal shell, so they do not shield one another as effectively as inner-shell electrons do.
Kartu 34
Pertanyaan
Which has the larger atomic radius, Li or Na?
Jawaban
Na. It lies below Li and has an additional occupied electron shell.
Kartu 35
Pertanyaan
Which has the larger atomic radius, Na or Mg?
Jawaban
Na. Atomic radius generally decreases from left to right across Period 3.
Kartu 36
Pertanyaan
How does greater electron–nucleus distance affect electrostatic attraction?
Jawaban
It weakens the attraction, all else being equal.
Kartu 37
Pertanyaan
How do successive ionization energies for one element compare?
Jawaban
Each successive ionization energy is higher than the one before it because an electron is removed from an increasingly positive species.
Kartu 38
Pertanyaan
Which has the higher first ionization energy, Li or Na?
Jawaban
Li. Its valence electron is closer to the nucleus and less shielded.
Kartu 39
Pertanyaan
Which has the higher first ionization energy, Na or Mg?
Jawaban
Mg. Its greater effective nuclear charge holds the valence electrons more tightly.
Kartu 40
Pertanyaan
Why does forming a cation usually shrink an atom?
Jawaban
Electron loss reduces electron–electron repulsion and increases the nuclear pull per remaining electron; losing the outer shell can shrink it sharply.
Kartu 41
Pertanyaan
Which element is most electronegative on the Pauling scale?
Jawaban
Fluorine.
Kartu 42
Pertanyaan
Which is more electronegative, Li or Na?
Jawaban
Li. Electronegativity generally decreases down Group 1.
Kartu 43
Pertanyaan
Which is more electronegative, Na or Mg?
Jawaban
Mg. Electronegativity generally increases across Period 3.
Kartu 44
Pertanyaan
What does a large jump between successive ionization energies reveal?
Jawaban
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.
Kartu 45
Pertanyaan
Why is Cl⁻ larger than neutral Cl?
Jawaban
The added electron increases repulsion within the valence shell while the nuclear charge stays the same.
Kartu 46
Pertanyaan
How do you compare the radii of isoelectronic species?
Jawaban
The species with more protons is smaller because the same number of electrons feels a stronger nuclear attraction.
Kartu 47
Pertanyaan
Why does an atom have no single sharp physical radius?
Jawaban
Its electron cloud has no hard edge, so atomic size depends on a defined measurement such as covalent, metallic, or van der Waals radius.
Kartu 48
Pertanyaan
Why are noble-gas electronegativities often omitted in introductory tables?
Jawaban
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.
Kartu 49
Pertanyaan
Why does forming an anion usually expand an atom?
Jawaban
The extra electron increases electron–electron repulsion and lowers the nuclear pull available per electron.
Kartu 50
Pertanyaan
Order O²⁻, F⁻, and Ne from largest to smallest radius.
Jawaban
O²⁻ > F⁻ > Ne. All have 10 electrons, and increasing proton count pulls that electron cloud inward.
Kartu 51
Pertanyaan
After which removal does Na show its first large ionization-energy jump?
Jawaban
After the first electron. Removing one valence electron leaves a stable core, so the second removal reaches that core.
Kartu 52
Pertanyaan
Does electronegativity difference create a universal ionic-versus-covalent cutoff?
Jawaban
No. A larger difference usually means more bond polarity, but bonding lies on a continuum and context matters.
Kartu 53
Pertanyaan
How do noble gases generally differ from halogens in electron affinity?
Jawaban
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.
Kartu 54
Pertanyaan
Which is smaller, Na⁺ or Mg²⁺?
Jawaban
Mg²⁺. Both have 10 electrons, but Mg²⁺ has one more proton.
Kartu 55
Pertanyaan
After which removal does Mg show its first large ionization-energy jump?
Jawaban
After the second electron. Mg has two valence electrons, so the third removal reaches a core shell.
Kartu 56
Pertanyaan
How does electronegativity differ from electron affinity?
Jawaban
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.
Kartu 57
Pertanyaan
How are atomic radius and first ionization energy generally related?
Jawaban
A larger radius usually means a lower first ionization energy because the valence electron is farther from the nucleus and easier to remove.
Kartu 58
Pertanyaan
Which has the more exothermic first electron affinity, F or Cl?
Jawaban
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.
Kartu 59
Pertanyaan
Which has the higher first ionization energy, Be or B?
Jawaban
Be. B loses a higher-energy 2p electron, while Be loses a more penetrating 2s electron from a filled 2s subshell.
Kartu 60
Pertanyaan
Why does Group 1 metal reactivity generally increase down the group?
Jawaban
The valence electron is farther out and more shielded, so its first ionization energy falls and electron loss becomes easier.
Kartu 61
Pertanyaan
How are atomic radius and electronegativity generally related?
Jawaban
Smaller atoms usually attract bonding electrons more strongly, so electronegativity tends to rise as radius falls.
Kartu 62
Pertanyaan
Why is Na⁺ much smaller than neutral Na?
Jawaban
Na loses its entire third-shell valence level, leaving the smaller neon-like electron configuration.
Kartu 63
Pertanyaan
Which has the higher first ionization energy, Mg or Al?
Jawaban
Mg. Al's removed electron is a higher-energy 3p electron, while Mg loses a more penetrating 3s electron from a filled 3s subshell.
Kartu 64
Pertanyaan
Why does halogen reactivity generally decrease down Group 17?
Jawaban
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.
Kartu 65
Pertanyaan
Why do Groups 2 and 15 often interrupt the simple electron-affinity trend?
Jawaban
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.
Kartu 66
Pertanyaan
Can ion charge alone rank two unrelated ionic radii?
Jawaban
No. Shell number, electron count, proton count, oxidation state, and crystal environment can all matter; the isoelectronic rule needs the same electron count.
Kartu 67
Pertanyaan
Which has the higher first ionization energy, N or O?
Jawaban
N. Its half-filled 2p subshell is relatively stable; O has one paired 2p orbital, and repulsion makes one electron easier to remove.
Kartu 68
Pertanyaan
In which direction does nonmetallic character generally increase?
Jawaban
Up and to the right, opposite the general trend in metallic character.
Kartu 69
Pertanyaan
Within the same principal shell, which penetrates closer to the nucleus: an s or p orbital?
Jawaban
An s orbital. Greater penetration means its electrons are less shielded and usually lower in energy than p electrons in the same shell.
Kartu 70
Pertanyaan
How do same-charge ion radii generally change down a group?
Jawaban
They increase as occupied electron shells are added.
Kartu 71
Pertanyaan
Which has the higher first ionization energy, P or S?
Jawaban
P. Its half-filled 3p subshell is relatively stable; S contains a paired 3p orbital that increases repulsion and eases removal.
Kartu 72
Pertanyaan
Why should simple periodic-direction rules be used cautiously for transition metals?
Jawaban
d-electron filling, shielding, oxidation state, and contraction effects make their property changes less regular than main-group trends.
Kartu 73
Pertanyaan
Why do periodic-trend statements usually say “generally”?
Jawaban
Subshell energies, electron pairing, radius definitions, and element-specific configurations create real exceptions to the broad patterns.
Kartu 74
Pertanyaan
Which has the larger atomic radius, K or Br?
Jawaban
K. Both are in Period 4, and atomic radius generally decreases from left to right.
Kartu 75
Pertanyaan
Which has the higher first ionization energy, Mg or Cl?
Jawaban
Cl. Its valence electrons experience greater effective nuclear charge and are held more tightly.
Kartu 76
Pertanyaan
Which is more electronegative, Al or Si?
Jawaban
Si. Electronegativity generally increases across Period 3.
Kartu 77
Pertanyaan
Which has the larger atomic radius, O or F?
Jawaban
O. Atomic radius generally decreases across Period 2.
Kartu 78
Pertanyaan
Which has the higher first ionization energy, K or Br?
Jawaban
Br. First ionization energy generally increases across Period 4.
Kartu 79
Pertanyaan
Which is more electronegative, Mg or Cl?
Jawaban
Cl. It lies farther right in Period 3.
Kartu 80
Pertanyaan
Which has the larger atomic radius, Al or Si?
Jawaban
Al. Atomic radius generally decreases across Period 3 as effective nuclear charge rises.
Kartu 81
Pertanyaan
Which has the higher first ionization energy, O or F?
Jawaban
F. This pair follows the general increase across Period 2.
Kartu 82
Pertanyaan
Which is more electronegative, K or Br?
Jawaban
Br. Electronegativity generally increases across Period 4.
Kartu 83
Pertanyaan
Which has the larger atomic radius, Mg or Cl?
Jawaban
Mg. Both are in Period 3, and Mg lies farther left.
Kartu 84
Pertanyaan
Which has the higher first ionization energy, Al or Si?
Jawaban
Si. This pair follows the general increase across Period 3.
Kartu 85
Pertanyaan
Which is more electronegative, O or F?
Jawaban
F, the most electronegative element on the Pauling scale.
Kartu 86
Pertanyaan
Order Al³⁺, Mg²⁺, Na⁺, Ne, F⁻, and O²⁻ from smallest to largest radius.
Jawaban
Al³⁺ < Mg²⁺ < Na⁺ < Ne < F⁻ < O²⁻. All have 10 electrons, so radius grows as proton count falls.
Kartu 87
Pertanyaan
Why do upper-right nonmetals usually hold valence electrons tightly?
Jawaban
Their relatively small radii and high effective nuclear charges create strong attraction between the nucleus and valence electrons.
Kartu 88
Pertanyaan
Across a main-group period, what shared cause links smaller radius, higher ionization energy, and higher electronegativity?
Jawaban
Increasing effective nuclear charge pulls the same-shell valence electrons inward and holds them more strongly.
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Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
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