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