Photographs of mineral crystals. All crystals are formed by positively and negatively charged atoms (ions) being attracted together. This sticking together of ions is called ionic bonding.
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Diagram showing arrangement of atoms in a salt crystal
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Some atoms, most notably carbon, hydrogen, oxygen, nitrogen, and sulfur, join together by sharing pairs of electrons. This known as covalent bonding.
Diagram showing sharing of electrons in a covalent bond
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