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