Copper is a transition element. Sodium is a Group 1 element. What are two differences between copper and sodium? Select two options.
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Copper has a lower melting point.
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Copper is harder.
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Copper is less dense.
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Copper is less reactive.
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Copper is less strong.
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Comparing the properties of transition metals (like copper) and Group 1 metals (like sodium):\n- **Hardness/Strength:** Transition metals are hard and strong. Group 1 metals are very soft. So, "Copper is harder" is correct.\n- **Reactivity:** Transition metals are generally unreactive. Group 1 metals are very reactive. So, "Copper is less reactive" is correct.\n- **Density:** Transition metals are dense. Group 1 metals have low densities (sodium floats on water). So, "Copper is less dense" is incorrect.\n- **Melting Point:** Transition metals have high melting and boiling points. Group 1 metals have low melting and boiling points. So, "Copper has a lower melting point" is incorrect.