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.
Bu destedeki kartlar
Kart 1
Soru
What is a periodic trend?
Cevap
A recurring pattern in element properties as atomic number increases across periods and down groups.
Kart 2
Soru
What does covalent radius measure?
Cevap
Half the distance between the nuclei of two identical atoms joined by a covalent bond.
Kart 3
Soru
What is first ionization energy?
Cevap
The minimum energy needed to remove the most loosely bound electron from an isolated gaseous atom in its ground state.
Kart 4
Soru
What is electronegativity?
Cevap
An atom's ability to attract shared electrons toward itself in a chemical bond.
Kart 5
Soru
What is a period on the periodic table?
Cevap
A horizontal row. For main-group elements, moving across a period fills orbitals in the same principal electron shell.
Kart 6
Soru
What is ionic radius?
Cevap
A measure of an ion's size, usually inferred from distances between ions in crystals.
Kart 7
Soru
What does electron affinity describe?
Cevap
The energy change when an electron is added to an isolated gaseous atom to form a gaseous anion.
Kart 8
Soru
What does metallic character describe?
Cevap
How readily an element shows metallic behavior, especially losing valence electrons and forming cations.
Kart 9
Soru
What is a group on the periodic table?
Cevap
A vertical column. Main-group elements in one group usually share a valence-electron pattern and similar chemistry.
Kart 10
Soru
What is effective nuclear charge?
Cevap
The net positive pull an electron feels from the nucleus after shielding and electron–electron repulsion are taken into account.
Kart 11
Soru
What are successive ionization energies?
Cevap
The energies needed to remove electrons one after another from the same atom, then from its increasingly positive ions.
Kart 12
Soru
How does electronegativity difference relate to bond polarity?
Cevap
A larger difference generally produces a more uneven electron distribution and a more polar bond.
Kart 13
Soru
Why do main-group elements in one group often behave similarly?
Cevap
They have the same general number and arrangement of valence electrons, which drive much of their bonding and reactivity.
Kart 14
Soru
What is electron shielding?
Cevap
The reduction in nuclear attraction felt by an electron because other electrons lie between it and the nucleus and repel it.
Kart 15
Soru
Why does the definition of ionization energy specify a gaseous atom?
Cevap
It isolates the atom from bonding and intermolecular effects, so the energy reflects electron removal from that species itself.
Kart 16
Soru
Where are metals and nonmetals generally found on the periodic table?
Cevap
Metals occupy the left and center; nonmetals cluster toward the upper right, with metalloids near the boundary.
Kart 17
Soru
What changes in the electron arrangement across a main-group period?
Cevap
Electrons are added to the same principal shell while the nucleus gains one proton from one element to the next.
Kart 18
Soru
How does atomic radius generally change from left to right across a period?
Cevap
It decreases.
Kart 19
Soru
How does first ionization energy generally change from left to right across a period?
Cevap
It increases, although a few recurring subshell and electron-pairing exceptions interrupt the rise.
Kart 20
Soru
How does electronegativity generally change from left to right across a period?
Cevap
It increases for the elements normally assigned electronegativity values.
Kart 21
Soru
What changes in the electron arrangement down a main-group group?
Cevap
Each step adds a higher principal electron shell while preserving a similar valence-electron pattern.
Kart 22
Soru
How does atomic radius generally change down a group?
Cevap
It increases.
Kart 23
Soru
How does first ionization energy generally change down a group?
Cevap
It decreases.
Kart 24
Soru
How does electronegativity generally change down a group?
Cevap
It decreases.
Kart 25
Soru
How does effective nuclear charge generally change across a main-group period?
Cevap
It increases because nuclear charge rises while added electrons enter the same principal shell and do not fully shield one another.
Kart 26
Soru
How does a cation's radius compare with its neutral parent atom?
Cevap
The cation is smaller.
Kart 27
Soru
How does electron addition generally change across a period?
Cevap
It generally becomes more energetically favorable toward the right, but electron affinity has substantial exceptions and depends on the sign convention used.
Kart 28
Soru
How does metallic character generally change from left to right across a period?
Cevap
It decreases.
Kart 29
Soru
Why are valence electrons generally farther from the nucleus down a group?
Cevap
They occupy shells with higher principal quantum numbers, so the electron cloud extends farther outward.
Kart 30
Soru
How does an anion's radius compare with its neutral parent atom?
Cevap
The anion is larger.
Kart 31
Soru
How does favorable electron addition generally change down a group?
Cevap
It generally becomes less favorable as the added electron enters a larger, more shielded shell, though electron-affinity irregularities are common.
Kart 32
Soru
How does metallic character generally change down a group?
Cevap
It increases.
Kart 33
Soru
Why does shielding change less than nuclear charge across a main-group period?
Cevap
The added electrons enter the same principal shell, so they do not shield one another as effectively as inner-shell electrons do.
Kart 34
Soru
Which has the larger atomic radius, Li or Na?
Cevap
Na. It lies below Li and has an additional occupied electron shell.
Kart 35
Soru
Which has the larger atomic radius, Na or Mg?
Cevap
Na. Atomic radius generally decreases from left to right across Period 3.
Kart 36
Soru
How does greater electron–nucleus distance affect electrostatic attraction?
Cevap
It weakens the attraction, all else being equal.
Kart 37
Soru
How do successive ionization energies for one element compare?
Cevap
Each successive ionization energy is higher than the one before it because an electron is removed from an increasingly positive species.
Kart 38
Soru
Which has the higher first ionization energy, Li or Na?
Cevap
Li. Its valence electron is closer to the nucleus and less shielded.
Kart 39
Soru
Which has the higher first ionization energy, Na or Mg?
Cevap
Mg. Its greater effective nuclear charge holds the valence electrons more tightly.
Kart 40
Soru
Why does forming a cation usually shrink an atom?
Cevap
Electron loss reduces electron–electron repulsion and increases the nuclear pull per remaining electron; losing the outer shell can shrink it sharply.
Kart 41
Soru
Which element is most electronegative on the Pauling scale?
Cevap
Fluorine.
Kart 42
Soru
Which is more electronegative, Li or Na?
Cevap
Li. Electronegativity generally decreases down Group 1.
Kart 43
Soru
Which is more electronegative, Na or Mg?
Cevap
Mg. Electronegativity generally increases across Period 3.
Kart 44
Soru
What does a large jump between successive ionization energies reveal?
Cevap
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.
Kart 45
Soru
Why is Cl⁻ larger than neutral Cl?
Cevap
The added electron increases repulsion within the valence shell while the nuclear charge stays the same.
Kart 46
Soru
How do you compare the radii of isoelectronic species?
Cevap
The species with more protons is smaller because the same number of electrons feels a stronger nuclear attraction.
Kart 47
Soru
Why does an atom have no single sharp physical radius?
Cevap
Its electron cloud has no hard edge, so atomic size depends on a defined measurement such as covalent, metallic, or van der Waals radius.
Kart 48
Soru
Why are noble-gas electronegativities often omitted in introductory tables?
Cevap
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.
Kart 49
Soru
Why does forming an anion usually expand an atom?
Cevap
The extra electron increases electron–electron repulsion and lowers the nuclear pull available per electron.
Kart 50
Soru
Order O²⁻, F⁻, and Ne from largest to smallest radius.
Cevap
O²⁻ > F⁻ > Ne. All have 10 electrons, and increasing proton count pulls that electron cloud inward.
Kart 51
Soru
After which removal does Na show its first large ionization-energy jump?
Cevap
After the first electron. Removing one valence electron leaves a stable core, so the second removal reaches that core.
Kart 52
Soru
Does electronegativity difference create a universal ionic-versus-covalent cutoff?
Cevap
No. A larger difference usually means more bond polarity, but bonding lies on a continuum and context matters.
Kart 53
Soru
How do noble gases generally differ from halogens in electron affinity?
Cevap
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.
Kart 54
Soru
Which is smaller, Na⁺ or Mg²⁺?
Cevap
Mg²⁺. Both have 10 electrons, but Mg²⁺ has one more proton.
Kart 55
Soru
After which removal does Mg show its first large ionization-energy jump?
Cevap
After the second electron. Mg has two valence electrons, so the third removal reaches a core shell.
Kart 56
Soru
How does electronegativity differ from electron affinity?
Cevap
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.
Kart 57
Soru
How are atomic radius and first ionization energy generally related?
Cevap
A larger radius usually means a lower first ionization energy because the valence electron is farther from the nucleus and easier to remove.
Kart 58
Soru
Which has the more exothermic first electron affinity, F or Cl?
Cevap
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.
Kart 59
Soru
Which has the higher first ionization energy, Be or B?
Cevap
Be. B loses a higher-energy 2p electron, while Be loses a more penetrating 2s electron from a filled 2s subshell.
Kart 60
Soru
Why does Group 1 metal reactivity generally increase down the group?
Cevap
The valence electron is farther out and more shielded, so its first ionization energy falls and electron loss becomes easier.
Kart 61
Soru
How are atomic radius and electronegativity generally related?
Cevap
Smaller atoms usually attract bonding electrons more strongly, so electronegativity tends to rise as radius falls.
Kart 62
Soru
Why is Na⁺ much smaller than neutral Na?
Cevap
Na loses its entire third-shell valence level, leaving the smaller neon-like electron configuration.
Kart 63
Soru
Which has the higher first ionization energy, Mg or Al?
Cevap
Mg. Al's removed electron is a higher-energy 3p electron, while Mg loses a more penetrating 3s electron from a filled 3s subshell.
Kart 64
Soru
Why does halogen reactivity generally decrease down Group 17?
Cevap
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.
Kart 65
Soru
Why do Groups 2 and 15 often interrupt the simple electron-affinity trend?
Cevap
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.
Kart 66
Soru
Can ion charge alone rank two unrelated ionic radii?
Cevap
No. Shell number, electron count, proton count, oxidation state, and crystal environment can all matter; the isoelectronic rule needs the same electron count.
Kart 67
Soru
Which has the higher first ionization energy, N or O?
Cevap
N. Its half-filled 2p subshell is relatively stable; O has one paired 2p orbital, and repulsion makes one electron easier to remove.
Kart 68
Soru
In which direction does nonmetallic character generally increase?
Cevap
Up and to the right, opposite the general trend in metallic character.
Kart 69
Soru
Within the same principal shell, which penetrates closer to the nucleus: an s or p orbital?
Cevap
An s orbital. Greater penetration means its electrons are less shielded and usually lower in energy than p electrons in the same shell.
Kart 70
Soru
How do same-charge ion radii generally change down a group?
Cevap
They increase as occupied electron shells are added.
Kart 71
Soru
Which has the higher first ionization energy, P or S?
Cevap
P. Its half-filled 3p subshell is relatively stable; S contains a paired 3p orbital that increases repulsion and eases removal.
Kart 72
Soru
Why should simple periodic-direction rules be used cautiously for transition metals?
Cevap
d-electron filling, shielding, oxidation state, and contraction effects make their property changes less regular than main-group trends.
Kart 73
Soru
Why do periodic-trend statements usually say “generally”?
Cevap
Subshell energies, electron pairing, radius definitions, and element-specific configurations create real exceptions to the broad patterns.
Kart 74
Soru
Which has the larger atomic radius, K or Br?
Cevap
K. Both are in Period 4, and atomic radius generally decreases from left to right.
Kart 75
Soru
Which has the higher first ionization energy, Mg or Cl?
Cevap
Cl. Its valence electrons experience greater effective nuclear charge and are held more tightly.
Kart 76
Soru
Which is more electronegative, Al or Si?
Cevap
Si. Electronegativity generally increases across Period 3.
Kart 77
Soru
Which has the larger atomic radius, O or F?
Cevap
O. Atomic radius generally decreases across Period 2.
Kart 78
Soru
Which has the higher first ionization energy, K or Br?
Cevap
Br. First ionization energy generally increases across Period 4.
Kart 79
Soru
Which is more electronegative, Mg or Cl?
Cevap
Cl. It lies farther right in Period 3.
Kart 80
Soru
Which has the larger atomic radius, Al or Si?
Cevap
Al. Atomic radius generally decreases across Period 3 as effective nuclear charge rises.
Kart 81
Soru
Which has the higher first ionization energy, O or F?
Cevap
F. This pair follows the general increase across Period 2.
Kart 82
Soru
Which is more electronegative, K or Br?
Cevap
Br. Electronegativity generally increases across Period 4.
Kart 83
Soru
Which has the larger atomic radius, Mg or Cl?
Cevap
Mg. Both are in Period 3, and Mg lies farther left.
Kart 84
Soru
Which has the higher first ionization energy, Al or Si?
Cevap
Si. This pair follows the general increase across Period 3.
Kart 85
Soru
Which is more electronegative, O or F?
Cevap
F, the most electronegative element on the Pauling scale.
Kart 86
Soru
Order Al³⁺, Mg²⁺, Na⁺, Ne, F⁻, and O²⁻ from smallest to largest radius.
Cevap
Al³⁺ < Mg²⁺ < Na⁺ < Ne < F⁻ < O²⁻. All have 10 electrons, so radius grows as proton count falls.
Kart 87
Soru
Why do upper-right nonmetals usually hold valence electrons tightly?
Cevap
Their relatively small radii and high effective nuclear charges create strong attraction between the nucleus and valence electrons.
Kart 88
Soru
Across a main-group period, what shared cause links smaller radius, higher ionization energy, and higher electronegativity?
Cevap
Increasing effective nuclear charge pulls the same-shell valence electrons inward and holds them more strongly.
88 kart
Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
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