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