The first 36 elements — hydrogen through krypton — with the symbol on the front and the name plus atomic number on the back. This is the span most intro chemistry courses expect on sight, and it covers the symbols that don't match their names.
Why the First 36
Elements 1–36 cover the first four periods: every element in the organic-chemistry core (C, H, N, O, P, S), the common metals (Fe, Cu, Zn, Al), the alkali and alkaline-earth columns, the halogens through bromine, and the first transition series. Past krypton, courses stop expecting recall and start handing you the table. If your class wants more, the deck is editable — add silver (Ag, 47), tin (Sn, 50), gold (Au, 79) and friends in the editor.
The Latin Traps
The cards that earn their keep are the symbols with Latin roots: Na (sodium, natrium), K (potassium, kalium), Fe (iron, ferrum), Cu (copper, cuprum) — plus tungsten's W waiting for you later. Drill symbol→name first (that's the direction exams test), then flip to name→symbol for writing formulas.