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Periodic Table Flashcards: Symbols, Groups and Trends

This starter set covers the facts a general chemistry course expects you to know cold: the symbols and atomic numbers of the common elements, the named groups, the s/p/d/f blocks, and the main periodic trends with the reason behind each. The cards follow the way the periodic table is introduced in OpenStax Chemistry 2e; some cards (diatomic elements, period lengths, group-number rules) are standard course content not taken from a specific page. It does not try to cover all 118 elements, so add the rest your instructor assigns from your own notes.

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Free Periodic Table flashcards: 31-card starter set

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Atomic number, mass number and symbols (9)

What does the atomic number (Z) of an element tell you?

The number of protons in the nucleus. It defines the element, and in a neutral atom it also equals the number of electrons.

How do you find the number of neutrons in an atom?

Mass number minus atomic number (A - Z). Isotopes of one element have the same Z but different numbers of neutrons.

Name elements 1 to 10 in order, with symbols.

H hydrogen, He helium, Li lithium, Be beryllium, B boron, C carbon, N nitrogen, O oxygen, F fluorine, Ne neon.

Name elements 11 to 20 in order, with symbols.

Na sodium, Mg magnesium, Al aluminum, Si silicon, P phosphorus, S sulfur, Cl chlorine, Ar argon, K potassium, Ca calcium.

Which common elements have symbols taken from Latin names? (Na, K, Fe, Cu)

Na = sodium (natrium), K = potassium (kalium), Fe = iron (ferrum), Cu = copper (cuprum).

Give the symbol and atomic number of silver, tin, gold, mercury and lead.

Silver Ag 47, tin Sn 50, gold Au 79, mercury Hg 80, lead Pb 82. All five symbols come from Latin or Greek names.

Give the atomic numbers of chromium, manganese, iron, cobalt, nickel, copper and zinc.

Cr 24, Mn 25, Fe 26, Co 27, Ni 28, Cu 29, Zn 30 (the first-row transition metals plus zinc).

What are the symbols and atomic numbers of bromine and iodine?

Br = 35 and I = 53. Chlorine (Cl) is 17 and fluorine (F) is 9, so the stable halogens run 9, 17, 35, 53.

Why does capitalization matter in symbols: Co versus CO?

Only the first letter of a symbol is capitalized. Co is the element cobalt; CO is carbon monoxide, a compound of carbon and oxygen.

Groups, periods and families (11)

What are periods and groups in the periodic table?

Periods are the 7 horizontal rows; groups are the 18 vertical columns (numbered 1-18 by IUPAC). Elements are ordered by increasing atomic number, and elements in a group behave similarly.

Which elements are the alkali metals, and what charge do their ions have?

Group 1 except hydrogen: Li, Na, K, Rb, Cs, Fr. Soft, very reactive metals that form 1+ ions.

Which elements are the alkaline earth metals, and what charge do their ions have?

Group 2: Be, Mg, Ca, Sr, Ba, Ra. They form 2+ ions and are less reactive than the alkali metals.

Which elements are the halogens, and what ion do they typically form?

Group 17: F, Cl, Br, I, At (and Ts). Reactive nonmetals that usually gain one electron to form 1- ions.

Which elements are the noble gases, and why are they unreactive?

Group 18: He, Ne, Ar, Kr, Xe, Rn. They have a full valence shell (2 electrons for He, 8 for the others), so they rarely form compounds.

What are chalcogens and pnictogens?

Chalcogens are group 16 (O, S, Se, Te, Po). Pnictogens are group 15 (N, P, As, Sb, Bi).

Which groups are the main-group elements and which are the transition metals?

Main-group (representative) elements are groups 1, 2 and 13-18. Transition metals are groups 3-12 (IUPAC does not count group 12, but many courses do).

What are the lanthanides and actinides?

The two rows shown below the main table, called the inner transition metals. They are the 4f and 5f series, placed below to keep the table narrow.

Which elements are usually classed as metalloids?

B, Si, Ge, As, Sb and Te (lists vary slightly, e.g. some add At). They conduct moderately well and show properties of both metals and nonmetals.

Which two elements are liquid at room temperature?

Bromine (a nonmetal) and mercury (a metal).

Which seven elements exist as diatomic molecules in their elemental form?

H2, N2, O2, F2, Cl2, Br2 and I2.

Blocks and valence electrons (4)

What are the s, p, d and f blocks of the periodic table?

s-block: groups 1-2 (plus He). p-block: groups 13-18. d-block: transition metals (groups 3-12). f-block: lanthanides and actinides. The block names the subshell being filled.

How is the period number related to electron configuration?

It equals the principal quantum number n of the outermost occupied shell. Period 3 elements fill n = 3, for example.

How does a main-group element's group number predict its valence electrons?

Groups 1 and 2 have 1 and 2 valence electrons. For groups 13-18 it is the group number minus 10 (3 to 8). Helium is the exception with 2.

How many elements are in periods 1 to 7?

2, 8, 8, 18, 18, 32, 32. The table currently ends at element 118, oganesson (Og).

Periodic trends (7)

How does atomic radius change across a period and down a group?

It decreases left to right across a period (higher effective nuclear charge pulls electrons in) and increases down a group (extra electron shells).

How does first ionization energy change across a period and down a group?

It generally increases across a period and decreases down a group, because valence electrons are held more tightly when closer and more strongly attracted.

Which two dips break the first ionization energy trend in period 2?

Boron is lower than beryllium, and oxygen is lower than nitrogen. Causes: subshell energy differences (2p vs 2s) and electron-pair repulsion in oxygen.

What is electronegativity and how does it trend?

The ability of an atom to attract bonding electrons. It generally increases across a period and decreases down a group. Fluorine is the most electronegative element.

Why is chlorine's electron affinity more negative than fluorine's?

Fluorine's small 2p subshell causes strong electron-electron repulsion when an electron is added, so chlorine releases more energy (about -349 kJ/mol for Cl versus -328 kJ/mol for F; some textbooks list -348 and -322).

Compare the size of a cation and an anion with its parent atom.

Cations are smaller than the parent atom (fewer electrons, less repulsion). Anions are larger (extra electrons, more repulsion).

How does metallic character change across a period and down a group?

It decreases left to right across a period and increases down a group, following the same pattern as atomic size.

What this set covers

Covered

Atomic number and symbols, elements 1-20 and common metals, named groups, blocks, periods, trends

Best used for

First-semester general chemistry quizzes and exams, and AP/IB chemistry review

Not covered

Every element, full electron configurations, exceptions beyond the standard trend breaks, isotopic masses

Card format

Short prompt on the front, short complete answer on the back

How to study this set

Element facts are pure recall, so short, frequent, out-loud sessions beat one long cram. Keep the symbols and the trends in separate passes, because they use different kinds of memory.

1
Day 1
Learn elements 1-20 in order. Write the symbols from memory on a blank grid before you flip each card, and say each name aloud.
2
Days 2-7
Add the Latin-symbol metals and the first-row transition metals. Review the missed cards daily; sort the table into families with your finger as you recite.
3
Week 2
Move to the trend cards. For each one, state the direction and the reason (nuclear charge or shell number) before checking the answer.
4
Final week
Mix everything and quiz backwards: from atomic number to symbol, then from a trend question to a named element. Redraw the blank table and label the groups and blocks from memory.

Spaced repetition schedules each card to come back just before you would forget it, so reviews get shorter as your recall gets stronger. Cards you miss come back sooner.

Common mistakes to avoid

Memorizing trends without the reason

Exam questions ask why ionization energy rises across a period. Learn the cause: effective nuclear charge increases while the shell number stays the same.

Forgetting the exceptions

Ionization energy dips at B and O in period 2, and electron affinity is not simply "bigger toward fluorine". Learn the two or three standard exceptions explicitly.

Mixing up group names and numbers

Alkali is group 1 but alkaline earth is group 2. Hydrogen sits in group 1 but is not an alkali metal.

Reciting symbols without writing them

Case matters (Co vs CO, Ca vs CA). Write each symbol rather than only recognizing it.

Make your own from your notes

A starter set is a head start, not your whole course. Your class notes, slides and textbook are what your teacher actually tests, so turn them into cards too.

Put the atomic number or the element name on the front and the symbol plus one fact on the back, so each card has a single target.
For trends, write the front as a comparison ("Which has the larger radius, Na or Cl, and why?") instead of a bare definition.
Paste only the elements your instructor assigned so the deck matches your exam list rather than the full table.
Avoid cards that list a whole group of five or more elements; split them into smaller cards you can answer in seconds.

Generate cards from a topic or notes Turn a PDF into flashcards

Periodic Table flashcards: questions

Do I need to memorize all 118 elements?

Most general chemistry courses expect the first 20 or so, the common metals and the named families. Your syllabus or instructor lists the exact set; use this deck for the core and add the rest from your own notes.

What is the difference between a group and a period?

A group is a vertical column and a period is a horizontal row. Elements in a group share valence electron counts and similar chemistry; the period tells you the outer shell number.

Is hydrogen an alkali metal?

No. Hydrogen is placed above group 1 because it has one valence electron, but it is a nonmetal and its properties also resemble group 17. The alkali metals are Li through Fr.

How many periodic table cards should I review per day?

Ten to twenty new cards plus whatever the spaced schedule shows is a reasonable load. Symbols are quick to review, so most sessions take a few minutes.

Are these cards enough for a chemistry final?

They cover the periodic table portion only. You will also need cards for bonding, stoichiometry and your course-specific topics. Treat this as an independent study aid and build the rest from your notes.

Sources and review

These cards are an independent study aid, not official exam content, and are not affiliated with or endorsed by any exam body or publisher. They were written by hand and checked against the sources below on 2026-10-17. Always confirm details with your course materials and the current official documents.

OpenStax Chemistry 2e: Atomic Structure and Symbolism — Read for the definitions of atomic number and mass number, the capitalization rule (Co vs CO) and the table of Latin-derived symbols.
OpenStax Chemistry 2e: The Periodic Table — Read for periods and groups, main-group and transition-metal grouping (groups 3-12), family names and the metal/nonmetal/metalloid classes.
OpenStax Chemistry 2e: Periodic Variations in Element Properties — Read for the radius, ionization energy, electron affinity and ion size trends, the B/Be and O/N exceptions, and the Cl versus F electron affinity explanation. Other cards are general reference written from standard course content.

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