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