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