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