STEM EVIDENCE WORKBENCH
Check bounded same-period and same-group comparison claims for atomic radius, first ionization energy, and electronegativity with a visible rule path.
Review output
Load the worked example to inspect realistic inputs, or enter anonymous classroom or laboratory evidence. Results remain in this browser tab until you copy or download them.
Transparent method
Across a period from left to right, effective nuclear charge generally rises while the principal occupied shell stays the same, so atomic radius generally decreases and first ionization energy and electronegativity generally increase. Down a group, additional occupied shells and shielding generally increase radius and reduce those two attraction-related properties. The engine reverses the comparison when element A appears later rather than earlier in the declared direction. A supported claim agrees with the implemented broad trend for the entered relation and positions. A conflict calls for checking element order, selected property, or whether the pair truly belongs to the same period or group. The result does not override measured values, subshell effects, noble-gas conventions, transition-metal behavior, or recognized ionization-energy exceptions. A strong explanation connects the trend to a physical model and acknowledges scope.
Confirm the prompt, source values, units, signs, notation, precision, and model required by the current course. Keep an untouched copy of observations or responses before changing a row.
Run the worked example first, inspect every intermediate row, and compare the table with a hand calculation, diagram, number line, periodic table, or approved laboratory method.
Record the method, assumptions, units, rounding, limits, and any row that needs review. Use the exported report as editable evidence and verify it independently before assessment or laboratory use.
How to interpret the result
Use this diagnostic when learners need to turn periodic-table position into a comparison and explanation. It is bounded to broad same-row or same-column trends so the direction of travel is unambiguous. The evidence table separates property, relation, general rule, expected comparison, and learner claim. It supports a follow-up explanation involving effective nuclear charge, shells, and shielding. It is not a complete database of measured values or known exceptions.
The worked set predicts sodium has a greater radius but lower first ionization energy than magnesium in the same period. Lithium has a smaller radius than sodium down their group, and fluorine has greater electronegativity than chlorine. The final row claims potassium has a smaller radius than calcium in the same period, conflicting with the broad left-to-right decrease. Each judgment shows the applied rule rather than a bare correct-or-incorrect mark.
Across a period from left to right, effective nuclear charge generally rises while the principal occupied shell stays the same, so atomic radius generally decreases and first ionization energy and electronegativity generally increase. Down a group, additional occupied shells and shielding generally increase radius and reduce those two attraction-related properties. The engine reverses the comparison when element A appears later rather than earlier in the declared direction.
A supported claim agrees with the implemented broad trend for the entered relation and positions. A conflict calls for checking element order, selected property, or whether the pair truly belongs to the same period or group. The result does not override measured values, subshell effects, noble-gas conventions, transition-metal behavior, or recognized ionization-energy exceptions. A strong explanation connects the trend to a physical model and acknowledges scope.
Do not use one arrow for every property, compare elements diagonally while declaring the same row or column, reverse group and period numbers, explain all trends only by nuclear charge, or treat a broad trend as exception-free data. Locate both elements, name the property, state the direction, discuss effective nuclear charge and shielding, check electron configuration when needed, and consult actual reference data when the question concerns measured values.
Learning boundary
This browser-local workbench applies only the disclosed rules to entered values. It cannot diagnose learning, establish a chemical structure, certify a measurement system, validate an experiment, or replace the method and judgment required by a teacher, curriculum, laboratory, or institution.
Review checklist
Practical questions
No. Processing occurs in the current browser tab. Avoid names and other personal information, and retain authoritative records only in the system approved by the school.
No. A matched pattern describes one entered response. Ask the learner to explain, use another representation, and review several evidence sources before deciding the next teaching step.
Treat it as an editable calculation aid. Show your own reasoning, use the method requested by the course, cite required sources, and follow the applicable academic-integrity rules.
YOUR NIRMION
