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Guilherme Mazui

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What is the Difference Between Homonuclear and Heteronuclear Diatomic Molecules?

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The main difference between homonuclear and heteronuclear diatomic molecules lies in the elements that make up the molecules.

  • Homonuclear diatomic molecules are composed of two atoms of the same element, such as hydrogen (H2), oxygen (O2), and nitrogen (N2). These molecules have a non-polar bond due to the electronegativity difference of zero. Examples of homonuclear diatomic molecules include hydrogen (H2), nitrogen (N2), oxygen (O2), fluorine (F2), chlorine (Cl2), bromine (Br2), and iodine (I2).
  • Heteronuclear diatomic molecules are composed of two atoms of different elements, such as hydrochloric acid (HCl) and carbon monoxide (CO). In these molecules, the bond is polar due to the electronegativity difference between the two elements. Examples of heteronuclear diatomic molecules include hydrogen chloride (HCl), hydrogen fluoride (HF), hydrogen bromide (HBr), hydrogen iodide (HI), carbon monoxide (CO), and nitric oxide (NO).

Both homonuclear and heteronuclear diatomic molecules share some common characteristics:

  • They are composed of only two atoms per molecule.
  • They have a linear geometry.
  • They contain covalent chemical bonds.
On this page
  • What is the Difference Between Homonuclear and Heteronuclear Diatomic Molecules?
  • Comparative Table: Homonuclear vs Heteronuclear Diatomic Molecules

    • Comparative Table: Homonuclear vs Heteronuclear Diatomic Molecules

    Here is a table comparing the differences between homonuclear and heteronuclear diatomic molecules:

    Feature Homonuclear Diatomic Molecules Heteronuclear Diatomic Molecules
    Definition Diatomic molecules containing two atoms of the same element. Diatomic molecules containing atoms of two different chemical elements.
    Electronegativity The two atoms in a homonuclear molecule have equal electronegativity, so the bond electron pairs are equally distributed, resulting in a nonpolar bond. The more electronegative atom has orbitals at a lower energy level, leading to a polar bond where atomic orbitals contribute unevenly to each molecular orbital.
    Bond Type Single, double, or triple bonds. Can be polar or nonpolar depending on the difference in electronegativity between the atoms.
    Examples Hydrogen (H2), nitrogen (N2), oxygen (O2), and halogens are common elements that form homonuclear diatomic molecules. Carbon monoxide (CO) and hydrogen fluoride (HF) are examples of heteronuclear diatomic molecules.

    In summary, homonuclear diatomic molecules consist of two atoms of the same element and have equal electronegativity, resulting in nonpolar bonds. In contrast, heteronuclear diatomic molecules have atoms of two different elements and exhibit unequal electronegativity, leading to polar bonds.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.