ss (\$A_r\$) of metal X.\n\nGive your answer to 1 decimal place.","markscheme":"- Calculates the sum of the mass contributions: $(191 \\times 37) + (193 \\times 63) = 19226$ M1\n- Divides by $100$ to find the weighted average: $\\frac{19226}{100} = 192.26$ M1\n- Rounds to 1 decimal place to give $192.3$ A1","marks":3,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"weighted_average","label":"Weighted average","steps":[{"type":"text","order":0,"title":"Use each abundance","content":"The relative atomic mass is a **weighted average**: an isotope that is more abundant contributes more to the answer. Use the mass number and percentage abundance for both isotopes.","highlights":[{"text":"mass numbers and percentage abundances","location":"specification"}]},{"type":"hyper_latex","block":{"nodes":[{"latex":"\\htmlData{anchor=first}{\\color{@sky}{191\\times37}}=7067"},{"latex":"\\htmlData{anchor=second}{\\color{@sky}{193\\times63}}=12159"},{"latex":"\\htmlData{anchor=total}{\\color{@orange}{(191\\times37)+(193\\times63)}}=\\color{@orange}{19226}"}],"highlights":[{"color":"orange","style":"text-color-with-background","anchor":"total"}]},"order":1,"title":"Find total contribution","description":"Multiply each mass number by its percentage abundance, then add the two contributions. This earns the first method mark."},{"type":"hyper_latex","block":{"nodes":[{"latex":"A_r=\\frac{\\htmlData{anchor=total}{\\color{@sky}{19226}}}{100}"},{"latex":"A_r=\\htmlData{anchor=answer}{\\color{@orange}{192.26}}"}],"highlights":[{"color":"sky","style":"text-color-with-background","anchor":"total"},{"color":"orange","style":"text-color-with-background","anchor":"answer"}],"connections":[{"to":"answer","from":"total","color":"sky","label":"divide by 100","style":"solid"}]},"order":2,"title":"Divide by 100","description":"The abundances are percentages, so divide the total by 100. This earns the second method mark."},{"type":"text","order":3,"title":"Round the answer","content":"To round $192.26$ to 1 decimal place, look at the second decimal digit: it is $6$, so round the tenths digit up.\n\n$$\\boxed{A_r=192.3}$$\n\nThis correct rounding earns the final accuracy mark.","highlights":[{"text":"Give your answer to 1 decimal place.","location":"specification"}]}]}],"generatedAt":"2026-07-21T04:05:39.211Z","modelVersion":"gpt-5.6-terra","explanationVersion":"v3"},"options":[]}],"options":[],"explanation":null,"firstAttemptFullMarks":null},{"id":"20b7f161-0bc0-46a6-b65e-c39dab698bcc","revisionId":"8640cdaf-0f1f-44b8-9373-40b732670841","questionNumber":null,"questionType":"LA","specification":"This question is about atomic structure and isotopes.\n\n![An atomic diagram of element X.](https://assets.mathsgenie.co.uk/aqa-qb/bb5ae62e-f9c6-4889-9b61-d1995f7ef39d.png)","difficulty":3,"difficultyBand":"medium","totalMarks":7,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"a82e3694-2904-4ad6-97ca-f73da3ea3823","label":"a","content":"Name the parts of the atom labeled **A** and **B**.\nChoose answers from: `electron`, `neutron`, `nucleus`, `proton`.","markscheme":"- Identifies **A** as a proton B1\n- Identifies **B** as a neutron B1","marks":2,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"identify_particle_symbols","label":"Identify the particle symbols","steps":[{"type":"text","order":0,"title":"Locate both arrows","content":"Both arrowheads point to individual particles in the central nucleus, so the answers must be either **proton** or **neutron**. An electron is shown on a shell outside the nucleus, while the nucleus is the whole central cluster.","highlights":[{"text":"Name the parts of the atom labeled **A** and **B**.","location":"specification"}]},{"type":"text","order":1,"title":"Identify particle A","content":"The arrow labelled **A** points to a white particle marked with a $+$ sign. A proton has positive charge, so **A is a proton**. This identification earns **B1**.","highlights":[{"text":"proton","location":"specification"}]},{"type":

Mass number	Percentage abundance (%)
191	37
193	63

Mass number	Percentage abundance (%)
191	37
193	63

A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

Question 8

A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes Questions

A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes

Question 8

A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes Questions