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