Atoms within a molecule are held together by chemical bonds. The primary types of chemical bonds are:
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Covalent Bonds: These bonds form when two atoms share one or more pairs of electrons. This sharing allows each atom to attain a full outer shell of electrons, achieving greater stability. For example, in a water molecule (H₂O), each hydrogen atom shares an electron with the oxygen atom.
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Ionic Bonds: These bonds occur when one atom donates an electron to another atom, creating ions (charged atoms). The electrostatic attraction between the positively charged ion (cation) and the negatively charged ion (anion) holds them together. An example of this is sodium chloride (NaCl), where sodium donates an electron to chlorine.
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Metallic Bonds: In metallic substances, atoms share a "sea of electrons" that are free to move, which gives metals their characteristic properties, such as conductivity and malleability. The positive metal ions are held together by the attraction to this electron cloud.
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Hydrogen Bonds: While not a primary bond like covalent or ionic bonds, hydrogen bonds are important in stabilizing the structure of molecules, especially in biological systems (e.g., maintaining the structure of DNA). These bonds occur due to the attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.
These interactions between atoms are crucial for the formation and stability of molecules, influencing their chemical and physical properties.