rmulaUrl":"https://www.ocr.org.uk/Images/705129-equation-sheet-physics-a.pdf","initialIndex":37,"initialQuestionWindow":[{"id":"e9dc4fec-d2b0-4185-bbec-156ef4cc904a","revisionId":"1e214d28-9a57-40b7-8906-e92a1ecb3d6d","questionNumber":null,"questionType":"LA","specification":"","difficulty":2,"difficultyBand":"easy","totalMarks":9,"sourceTitle":null,"calculatorUse":null,"parts":[{"id":"830093df-ff42-4b8e-8ec6-664c63f5db04","label":"a","content":"Complete the sentences about the structure and behavior of atoms.\n\nUse words from the list.\n\nYou may use each word once, more than once, or not at all.\n\n* **Electrons**\n* **Mass**\n* **Negative**\n* **Neutrons**\n* **Nucleus**\n* **Positive**\n* **Protons**\n* **Repel**\n* **Volume**\n* **Zero**\n\n1. In an atom, the particle that has a negative charge is the ................................................ .\n2. Compared to a proton, a neutron has an electrical charge of ................................................ .\n3. The vast majority of the atom's ................................................ is concentrated in the nucleus.\n4. Particles with like charges, such as two protons, will naturally ................................................ each other.","markscheme":"- 1. Electrons B1\n- 2. Zero B1\n- 3. Mass B1\n- 4. Repel B1","marks":4,"order":0,"markingRubric":null,"explanation":{"methods":[{"id":"atomic_structure","label":"Recall particle properties","steps":[{"type":"text","order":0,"title":"Match the charged particle","content":"For sentence 1, an **electron** is the subatomic particle with a negative electrical charge. Write **Electrons** in the first gap. This earns the first B1 mark.","highlights":[{"text":"the particle that has a negative charge","location":"specification"}]},{"type":"text","order":1,"title":"Recall the neutron charge","content":"For sentence 2, a neutron has no electrical charge: its charge is **zero**. Write **Zero**. This earns the second B1 mark.","highlights":[{"text":"a neutron has an electrical charge of","location":"specification"}]},{"type":"text","order":2,"title":"Identify where mass is","content":"For sentence 3, the nucleus contains protons and neutrons. These are much heavier than electrons, so nearly all of an atom’s **mass** is in its nucleus. Write **Mass** for the third B1 mark.","highlights":[{"text":"The vast majority of the atom's","location":"specification"},{"text":"is concentrated in the nucleus.","location":"specification"}]},{"type":"text","order":3,"title":"Use the force rule","content":"For sentence 4, like charges push apart. Therefore two positive protons **repel** each other. Write **Repel** to earn the final B1 mark.","highlights":[{"text":"Particles with like charges, such as two protons, will naturally","location":"specification"}]}]}],"generatedAt":"2026-07-22T12:11:07.929Z","modelVersion":"gpt-5.6-terra+diagrams-1","explanationVersion":"v3"},"options":[]},{"id":"eda077b1-1343-4097-9ed0-a9cfe72785ba","label":"b","content":"A block of titanium has a mass of \$11250\\text{ kg}\$ and a volume of \$2.5\\text{ m}^3\$.\n\nCalculate the density of titanium.\n\nUse the equation: \\[\\text{density} = \\frac{\\text{mass}}{\\text{volume}}\\]\n\nDensity = ................................................ \$\\text{kg/m}^3\$","markscheme":"- (i) Recalls or uses $\\text{density} = \\frac{11250}{2.5}$ M1\n- (i) Correctly calculates density as $4500\\text{ kg/m}^3$ A1","marks":2,"order":1,"markingRubric":null,"explanation":{"methods":[{"id":"use_density_equation","label":"Use the density equation","steps":[{"type":"text","order":0,"title":"Substitute into the equation","content":"Substitute the given values into the formula. This substitution earns the M1 mark.\n\n$$\\text{density}=\\frac{\\text{mass}}{\\text{volume}}$$\n\n$$\\text{density}=\\frac{11250}{2.5}$$","highlights":[{"text":"A block of titanium has a mass of \$11250\\text{ kg}\$ and a volume of \$2.5\\text{ m}^3\$.","location":"specification"}]},{"type":"tex

The particle model

Question 15

The particle model Questions

The particle model

Question 15

The particle model Questions