Metals and non-metals: properties, position and ions
| English | 中文 | Pinyin |
|---|---|---|
| metal/ˈmetl/ | 金属 | jīn shǔ |
| non-metal/nɒn ˈmetl/ | 非金属 | fēi jīn shǔ |
What would explain this observation?
- Sodium and sulfur are both solids in the same period, but their electron arrangements and reactions differ. A single property such as being solid cannot identify a metal 金属.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- Most elements are metals, located toward the left and bottom of the periodic table. Non-metals 非金属 are mainly toward the right and top. Metals characteristically conduct electricity and heat, are often strong and malleable, and react to form positive ions by losing electrons. Non-metals generally conduct poorly and, when solid, are often brittle; many occur as gases. In the specified ionic reactions, non-metals may gain electrons to form negative ions.
- metal: An element characteristically conducting electricity and forming positive ions in its specified chemical reactions; non-metal: An element generally lacking metallic properties, often gaining or sharing electrons in specified reactions.
How does a sodium atom form Na⁺?
Sodium, 2,8,1, loses its outer electron to form Na⁺. Chlorine, 2,8,7, gains one to form Cl⁻. Oppositely charged ions can form a compound. Non-metal atoms also share electrons in covalent molecules, rather than always becoming isolated negative ions. Characteristic property patterns have exceptions: graphite conducts electricity and mercury is a liquid metal. Use more than one line of evidence.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Sodium, 2,8,1, loses its outer electron to form Na⁺. Chlorine, 2,8,7, gains one to form Cl⁻. Oppositely charged ions can form a compound. Non-metal atoms also share electrons in covalent molecules, rather than always becoming isolated negative ions. Characteristic property patterns have exceptions: graphite conducts electricity and mercury is a liquid metal. Use more than one line of evidence.
- Compare teacher-provided property cards, conductivity observations and electronic structures. Choose a classification, explain the electron change in a specified reaction and name a limitation of a physical-property inference. Use pre-approved specimens and supervised low-voltage conductivity apparatus; do not attempt reactions with unknown materials to discover their identity.
Which two habits make the investigation or model in this case more defensible?
Compare teacher-provided property cards, conductivity observations and electronic structures. Choose a classification, explain the electron change in a specified reaction and name a limitation of a physical-property inference. Use pre-approved specimens and supervised low-voltage conductivity apparatus; do not attempt reactions with unknown materials to discover their identity.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: four neutral sodium atoms each lose one electron when forming four Na⁺ ions. Four electrons are transferred in total; the four nuclei each retain eleven protons. Four chlorine atoms gaining those electrons form four Cl⁻ ions. The charges balance, but the electron transfer does not turn sodium nuclei into chlorine nuclei.
How many electrons are lost when six neutral sodium atoms each form Na⁺? Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
How many electrons are lost when six neutral sodium atoms each form Na⁺?
The result is 6 electrons. Known: four neutral sodium atoms each lose one electron when forming four Na⁺ ions. Four electrons are transferred in total; the four nuclei each retain eleven protons. Four chlorine atoms gaining those electrons form four Cl⁻ ions. The charges balance, but the electron transfer does not turn sodium nuclei into chlorine nuclei.
Check the conclusion and its limits
- Losing negative electrons makes an ion positive. Metals do not lose protons during normal chemical reactions. Non-metal does not mean gas, and shiny appearance alone is insufficient evidence. The simplified GCSE ion classification describes the reactions in scope rather than every possible ion in advanced chemistry.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
All non-metals are gases and none can conduct electricity. This claim is false: Losing negative electrons makes an ion positive. Metals do not lose protons during normal chemical reactions. Non-metal does not mean gas, and shiny appearance alone is insufficient evidence. The simplified GCSE ion classification describes the reactions in scope rather than every possible ion in advanced chemistry.
Metals and non-metals: properties, position and ions: Sodium, 2,8,1, loses its outer electron to form Na⁺. Chlorine, 2,8,7, gains one to form Cl⁻. Oppositely charged ions can form a compound. Non-metal atoms also share electrons in covalent molecules, rather than always becoming isolated negative ions. Characteristic property patterns have exceptions: graphite conducts electricity and mercury is a liquid metal. Use more than one line of evidence.
All non-metals are gases and none can conduct electricity.
Losing negative electrons makes an ion positive. Metals do not lose protons during normal chemical reactions. Non-metal does not mean gas, and shiny appearance alone is insufficient evidence. The simplified GCSE ion classification describes the reactions in scope rather than every possible ion in advanced chemistry.
An element characteristically conducting electricity and forming positive ions in its specified chemical reactions: write the technical term.
metal means An element characteristically conducting electricity and forming positive ions in its specified chemical reactions.