Original SVG and matching one-page A4 210 × 297 mm selectable-text PDF are linked below. The PDFs are untagged, so the full text on this page is the reliable screen-reader route. Number, word and reading order carry meaning without colour. Print at actual size, cut full-word cards, add a raised line or spacer if useful, or read the words aloud. A tactile route here is a paper arrangement, not a specialist-tested tactile graphic.
Atom model and its limits · PDF
Top statement: “A picture can show parts; it is not a measured path.” A schematic central NUCLEUS contains positive protons (p+) and neutral neutrons (n0). Outside, negative electrons (e−) are represented on energy level 1 and energy level 2 rings. These rings/dots are a convention, not circular electron tracks. The drawing is not to scale, does not identify a particular element, and does not give actual electron positions, paths or particle counts. Bottom words: positive protons and neutral neutrons—nucleus; negative electrons—represented in energy levels outside; counts require Z, A and charge. Tactile route: stack a central “nucleus / protons positive / neutrons neutral” card, an “electrons negative / outside” card, then two numbered energy-level cards; place a raised “model, not measured path” strip across the whole set. Do not imply the raised curves are physical trajectories.
A, Z and charge count mat · PDF
Read in order. GIVEN: element/name, integer A, integer Z, charge q in elementary-charge units. DERIVE: 1 protons p=Z; 2 neutrons n=A−Z; 3 electrons e=Z−q for the specified monoatomic atom/ion; 4 reverse checks p+n=A, p−e=q. 2+ means q=+2. Blank charge means neutral only if the task says so. Worked neutral example: carbon-12, A12 Z6 q0 → p6, n6, e6; checks 6+6=12 and 6−6=0. A is an integer count for an isotope, not decimal standard atomic weight. Tactile route: four numbered full-word rows plus movable A/Z/q number cards; put counts on the row then read the reverse check aloud.
Isotope or ion decision fork · PDF
Branch 1 · isotope comparison: neutral carbon-12 Z6 has p6 n6 e6; neutral carbon-13 Z6 has p6 n7 e6. Same element/Z, different neutron count/A: the nucleus differs. These cards do not state abundance or radioactivity. Branch 2 · charge comparison: neutral magnesium-24 has p12 n12 e12; magnesium-24 2+ has p12 n12 e10. Same isotope/nucleus, different electron count: the charge differs. The card does not show a real reaction. Bottom decision order: same Z? same A? same e? Tactile route: make two separate pairs of full-word cards; align proton/neutron/electron counts in three columns and mark the changed column with a raised token. The words “nucleus differs” or “electron count differs” remain attached.
The source examples are explained in original model cards, with rights separate from the DejaVu font notice.