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Illustrate how covalent bonds are formed in simple molecules such as H₂, Cl₂, H₂O, CH₄, NH₃, and C₂H₄, using dot-and-cross diagrams to represent their electronic configurations.

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Cambridge IGCSE Combined ScienceAtoms, elements and compoundsCore content

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Illustrate how covalent bonds are formed in simple molecules such as H₂, Cl₂, H₂O, CH₄, NH₃, and C₂H₄, using dot-and-cross diagrams to represent their electronic configurations

This point belongs to Simple molecules and covalent bonds, especially Simple molecules and covalent bonds outcomes.
You need to be able to illustrate how covalent bonds are formed in simple molecules such as H₂, Cl₂, H₂O, CH₄, NH₃, and C₂H₄, using dot-and-cross diagrams to represent their electronic configurations.
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Paper 3 structured question: Simple molecules and covalent bonds

Paper 3Theory (Core)3 marks

Description

Covalent Bonds in Molecules

Consider the following molecules: H₂, Cl₂, H₂O, CH₄, NH₃, and C₂H₄. Each of these molecules is formed by covalent bonds where atoms share electrons.

a
Describe the formation of covalent bonds in H₂ and H₂O using dot-and-cross diagrams.
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Related learning objectives

Explain that a covalent bond occurs when two atoms share a pair of electrons, resulting in electronic configurations similar to noble gases.
Simple molecules and covalent bonds outcomes
Outline the characteristics of simple molecular compounds, including their low melting and boiling points, as well as their poor electrical conductivity.
Simple molecules and covalent bonds outcomes
Explain the formation of covalent bonds in additional simple molecules such as CH₃OH, C₂H₄, O₂, CO, and N₂, using dot-and-cross diagrams to depict their electronic configurations.
Simple molecules and covalent bonds outcomes

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