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.
حول هذه الرزمة
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.
بطاقات هذه الرزمة
البطاقة ١
السؤال
What is a periodic trend?
الإجابة
A recurring pattern in element properties as atomic number increases across periods and down groups.
البطاقة ٢
السؤال
What does covalent radius measure?
الإجابة
Half the distance between the nuclei of two identical atoms joined by a covalent bond.
البطاقة ٣
السؤال
What is first ionization energy?
الإجابة
The minimum energy needed to remove the most loosely bound electron from an isolated gaseous atom in its ground state.
البطاقة ٤
السؤال
What is electronegativity?
الإجابة
An atom's ability to attract shared electrons toward itself in a chemical bond.
البطاقة ٥
السؤال
What is a period on the periodic table?
الإجابة
A horizontal row. For main-group elements, moving across a period fills orbitals in the same principal electron shell.
البطاقة ٦
السؤال
What is ionic radius?
الإجابة
A measure of an ion's size, usually inferred from distances between ions in crystals.
البطاقة ٧
السؤال
What does electron affinity describe?
الإجابة
The energy change when an electron is added to an isolated gaseous atom to form a gaseous anion.
البطاقة ٨
السؤال
What does metallic character describe?
الإجابة
How readily an element shows metallic behavior, especially losing valence electrons and forming cations.
البطاقة ٩
السؤال
What is a group on the periodic table?
الإجابة
A vertical column. Main-group elements in one group usually share a valence-electron pattern and similar chemistry.
البطاقة ١٠
السؤال
What is effective nuclear charge?
الإجابة
The net positive pull an electron feels from the nucleus after shielding and electron–electron repulsion are taken into account.
البطاقة ١١
السؤال
What are successive ionization energies?
الإجابة
The energies needed to remove electrons one after another from the same atom, then from its increasingly positive ions.
البطاقة ١٢
السؤال
How does electronegativity difference relate to bond polarity?
الإجابة
A larger difference generally produces a more uneven electron distribution and a more polar bond.
البطاقة ١٣
السؤال
Why do main-group elements in one group often behave similarly?
الإجابة
They have the same general number and arrangement of valence electrons, which drive much of their bonding and reactivity.
البطاقة ١٤
السؤال
What is electron shielding?
الإجابة
The reduction in nuclear attraction felt by an electron because other electrons lie between it and the nucleus and repel it.
البطاقة ١٥
السؤال
Why does the definition of ionization energy specify a gaseous atom?
الإجابة
It isolates the atom from bonding and intermolecular effects, so the energy reflects electron removal from that species itself.
البطاقة ١٦
السؤال
Where are metals and nonmetals generally found on the periodic table?
الإجابة
Metals occupy the left and center; nonmetals cluster toward the upper right, with metalloids near the boundary.
البطاقة ١٧
السؤال
What changes in the electron arrangement across a main-group period?
الإجابة
Electrons are added to the same principal shell while the nucleus gains one proton from one element to the next.
البطاقة ١٨
السؤال
How does atomic radius generally change from left to right across a period?
الإجابة
It decreases.
البطاقة ١٩
السؤال
How does first ionization energy generally change from left to right across a period?
الإجابة
It increases, although a few recurring subshell and electron-pairing exceptions interrupt the rise.
البطاقة ٢٠
السؤال
How does electronegativity generally change from left to right across a period?
الإجابة
It increases for the elements normally assigned electronegativity values.
البطاقة ٢١
السؤال
What changes in the electron arrangement down a main-group group?
الإجابة
Each step adds a higher principal electron shell while preserving a similar valence-electron pattern.
البطاقة ٢٢
السؤال
How does atomic radius generally change down a group?
الإجابة
It increases.
البطاقة ٢٣
السؤال
How does first ionization energy generally change down a group?
الإجابة
It decreases.
البطاقة ٢٤
السؤال
How does electronegativity generally change down a group?
الإجابة
It decreases.
البطاقة ٢٥
السؤال
How does effective nuclear charge generally change across a main-group period?
الإجابة
It increases because nuclear charge rises while added electrons enter the same principal shell and do not fully shield one another.
البطاقة ٢٦
السؤال
How does a cation's radius compare with its neutral parent atom?
الإجابة
The cation is smaller.
البطاقة ٢٧
السؤال
How does electron addition generally change across a period?
الإجابة
It generally becomes more energetically favorable toward the right, but electron affinity has substantial exceptions and depends on the sign convention used.
البطاقة ٢٨
السؤال
How does metallic character generally change from left to right across a period?
الإجابة
It decreases.
البطاقة ٢٩
السؤال
Why are valence electrons generally farther from the nucleus down a group?
الإجابة
They occupy shells with higher principal quantum numbers, so the electron cloud extends farther outward.
البطاقة ٣٠
السؤال
How does an anion's radius compare with its neutral parent atom?
الإجابة
The anion is larger.
البطاقة ٣١
السؤال
How does favorable electron addition generally change down a group?
الإجابة
It generally becomes less favorable as the added electron enters a larger, more shielded shell, though electron-affinity irregularities are common.
البطاقة ٣٢
السؤال
How does metallic character generally change down a group?
الإجابة
It increases.
البطاقة ٣٣
السؤال
Why does shielding change less than nuclear charge across a main-group period?
الإجابة
The added electrons enter the same principal shell, so they do not shield one another as effectively as inner-shell electrons do.
البطاقة ٣٤
السؤال
Which has the larger atomic radius, Li or Na?
الإجابة
Na. It lies below Li and has an additional occupied electron shell.
البطاقة ٣٥
السؤال
Which has the larger atomic radius, Na or Mg?
الإجابة
Na. Atomic radius generally decreases from left to right across Period 3.
البطاقة ٣٦
السؤال
How does greater electron–nucleus distance affect electrostatic attraction?
الإجابة
It weakens the attraction, all else being equal.
البطاقة ٣٧
السؤال
How do successive ionization energies for one element compare?
الإجابة
Each successive ionization energy is higher than the one before it because an electron is removed from an increasingly positive species.
البطاقة ٣٨
السؤال
Which has the higher first ionization energy, Li or Na?
الإجابة
Li. Its valence electron is closer to the nucleus and less shielded.
البطاقة ٣٩
السؤال
Which has the higher first ionization energy, Na or Mg?
الإجابة
Mg. Its greater effective nuclear charge holds the valence electrons more tightly.
البطاقة ٤٠
السؤال
Why does forming a cation usually shrink an atom?
الإجابة
Electron loss reduces electron–electron repulsion and increases the nuclear pull per remaining electron; losing the outer shell can shrink it sharply.
البطاقة ٤١
السؤال
Which element is most electronegative on the Pauling scale?
الإجابة
Fluorine.
البطاقة ٤٢
السؤال
Which is more electronegative, Li or Na?
الإجابة
Li. Electronegativity generally decreases down Group 1.
البطاقة ٤٣
السؤال
Which is more electronegative, Na or Mg?
الإجابة
Mg. Electronegativity generally increases across Period 3.
البطاقة ٤٤
السؤال
What does a large jump between successive ionization energies reveal?
الإجابة
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.
البطاقة ٤٥
السؤال
Why is Cl⁻ larger than neutral Cl?
الإجابة
The added electron increases repulsion within the valence shell while the nuclear charge stays the same.
البطاقة ٤٦
السؤال
How do you compare the radii of isoelectronic species?
الإجابة
The species with more protons is smaller because the same number of electrons feels a stronger nuclear attraction.
البطاقة ٤٧
السؤال
Why does an atom have no single sharp physical radius?
الإجابة
Its electron cloud has no hard edge, so atomic size depends on a defined measurement such as covalent, metallic, or van der Waals radius.
البطاقة ٤٨
السؤال
Why are noble-gas electronegativities often omitted in introductory tables?
الإجابة
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.
البطاقة ٤٩
السؤال
Why does forming an anion usually expand an atom?
الإجابة
The extra electron increases electron–electron repulsion and lowers the nuclear pull available per electron.
البطاقة ٥٠
السؤال
Order O²⁻, F⁻, and Ne from largest to smallest radius.
الإجابة
O²⁻ > F⁻ > Ne. All have 10 electrons, and increasing proton count pulls that electron cloud inward.
البطاقة ٥١
السؤال
After which removal does Na show its first large ionization-energy jump?
الإجابة
After the first electron. Removing one valence electron leaves a stable core, so the second removal reaches that core.
البطاقة ٥٢
السؤال
Does electronegativity difference create a universal ionic-versus-covalent cutoff?
الإجابة
No. A larger difference usually means more bond polarity, but bonding lies on a continuum and context matters.
البطاقة ٥٣
السؤال
How do noble gases generally differ from halogens in electron affinity?
الإجابة
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.
البطاقة ٥٤
السؤال
Which is smaller, Na⁺ or Mg²⁺?
الإجابة
Mg²⁺. Both have 10 electrons, but Mg²⁺ has one more proton.
البطاقة ٥٥
السؤال
After which removal does Mg show its first large ionization-energy jump?
الإجابة
After the second electron. Mg has two valence electrons, so the third removal reaches a core shell.
البطاقة ٥٦
السؤال
How does electronegativity differ from electron affinity?
الإجابة
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.
البطاقة ٥٧
السؤال
How are atomic radius and first ionization energy generally related?
الإجابة
A larger radius usually means a lower first ionization energy because the valence electron is farther from the nucleus and easier to remove.
البطاقة ٥٨
السؤال
Which has the more exothermic first electron affinity, F or Cl?
الإجابة
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.
البطاقة ٥٩
السؤال
Which has the higher first ionization energy, Be or B?
الإجابة
Be. B loses a higher-energy 2p electron, while Be loses a more penetrating 2s electron from a filled 2s subshell.
البطاقة ٦٠
السؤال
Why does Group 1 metal reactivity generally increase down the group?
الإجابة
The valence electron is farther out and more shielded, so its first ionization energy falls and electron loss becomes easier.
البطاقة ٦١
السؤال
How are atomic radius and electronegativity generally related?
الإجابة
Smaller atoms usually attract bonding electrons more strongly, so electronegativity tends to rise as radius falls.
البطاقة ٦٢
السؤال
Why is Na⁺ much smaller than neutral Na?
الإجابة
Na loses its entire third-shell valence level, leaving the smaller neon-like electron configuration.
البطاقة ٦٣
السؤال
Which has the higher first ionization energy, Mg or Al?
الإجابة
Mg. Al's removed electron is a higher-energy 3p electron, while Mg loses a more penetrating 3s electron from a filled 3s subshell.
البطاقة ٦٤
السؤال
Why does halogen reactivity generally decrease down Group 17?
الإجابة
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.
البطاقة ٦٥
السؤال
Why do Groups 2 and 15 often interrupt the simple electron-affinity trend?
الإجابة
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.
البطاقة ٦٦
السؤال
Can ion charge alone rank two unrelated ionic radii?
الإجابة
No. Shell number, electron count, proton count, oxidation state, and crystal environment can all matter; the isoelectronic rule needs the same electron count.
البطاقة ٦٧
السؤال
Which has the higher first ionization energy, N or O?
الإجابة
N. Its half-filled 2p subshell is relatively stable; O has one paired 2p orbital, and repulsion makes one electron easier to remove.
البطاقة ٦٨
السؤال
In which direction does nonmetallic character generally increase?
الإجابة
Up and to the right, opposite the general trend in metallic character.
البطاقة ٦٩
السؤال
Within the same principal shell, which penetrates closer to the nucleus: an s or p orbital?
الإجابة
An s orbital. Greater penetration means its electrons are less shielded and usually lower in energy than p electrons in the same shell.
البطاقة ٧٠
السؤال
How do same-charge ion radii generally change down a group?
الإجابة
They increase as occupied electron shells are added.
البطاقة ٧١
السؤال
Which has the higher first ionization energy, P or S?
الإجابة
P. Its half-filled 3p subshell is relatively stable; S contains a paired 3p orbital that increases repulsion and eases removal.
البطاقة ٧٢
السؤال
Why should simple periodic-direction rules be used cautiously for transition metals?
الإجابة
d-electron filling, shielding, oxidation state, and contraction effects make their property changes less regular than main-group trends.
البطاقة ٧٣
السؤال
Why do periodic-trend statements usually say “generally”?
الإجابة
Subshell energies, electron pairing, radius definitions, and element-specific configurations create real exceptions to the broad patterns.
البطاقة ٧٤
السؤال
Which has the larger atomic radius, K or Br?
الإجابة
K. Both are in Period 4, and atomic radius generally decreases from left to right.
البطاقة ٧٥
السؤال
Which has the higher first ionization energy, Mg or Cl?
الإجابة
Cl. Its valence electrons experience greater effective nuclear charge and are held more tightly.
البطاقة ٧٦
السؤال
Which is more electronegative, Al or Si?
الإجابة
Si. Electronegativity generally increases across Period 3.
البطاقة ٧٧
السؤال
Which has the larger atomic radius, O or F?
الإجابة
O. Atomic radius generally decreases across Period 2.
البطاقة ٧٨
السؤال
Which has the higher first ionization energy, K or Br?
الإجابة
Br. First ionization energy generally increases across Period 4.
البطاقة ٧٩
السؤال
Which is more electronegative, Mg or Cl?
الإجابة
Cl. It lies farther right in Period 3.
البطاقة ٨٠
السؤال
Which has the larger atomic radius, Al or Si?
الإجابة
Al. Atomic radius generally decreases across Period 3 as effective nuclear charge rises.
البطاقة ٨١
السؤال
Which has the higher first ionization energy, O or F?
الإجابة
F. This pair follows the general increase across Period 2.
البطاقة ٨٢
السؤال
Which is more electronegative, K or Br?
الإجابة
Br. Electronegativity generally increases across Period 4.
البطاقة ٨٣
السؤال
Which has the larger atomic radius, Mg or Cl?
الإجابة
Mg. Both are in Period 3, and Mg lies farther left.
البطاقة ٨٤
السؤال
Which has the higher first ionization energy, Al or Si?
الإجابة
Si. This pair follows the general increase across Period 3.
البطاقة ٨٥
السؤال
Which is more electronegative, O or F?
الإجابة
F, the most electronegative element on the Pauling scale.
البطاقة ٨٦
السؤال
Order Al³⁺, Mg²⁺, Na⁺, Ne, F⁻, and O²⁻ from smallest to largest radius.
الإجابة
Al³⁺ < Mg²⁺ < Na⁺ < Ne < F⁻ < O²⁻. All have 10 electrons, so radius grows as proton count falls.
البطاقة ٨٧
السؤال
Why do upper-right nonmetals usually hold valence electrons tightly?
الإجابة
Their relatively small radii and high effective nuclear charges create strong attraction between the nucleus and valence electrons.
البطاقة ٨٨
السؤال
Across a main-group period, what shared cause links smaller radius, higher ionization energy, and higher electronegativity?
الإجابة
Increasing effective nuclear charge pulls the same-shell valence electrons inward and holds them more strongly.
٨٨ بطاقة
Periodic Trends Flashcards: Atomic Radius, Ionization Energy & Electronegativity
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