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Atoms with equal numbers of protons but a different number of neutrons are different isotopes of the same element. For example, all hydrogen atoms admit exactly one proton, but isotopes exist with no neutrons (hydrogen-1, by far the most common form, [57] also called protium), one neutron , two neutrons and more than two neutrons.
Ever since Dalton's atoms and Kekulé's benzene, there has been a rich history of hand-drawn atoms and molecules, and these representations have had an important influence on modern molecular graphics. Colour molecular graphics are often used on chemistry journal covers artistically. [3]
This is an index of lists of molecules (i.e. by year, number of atoms, etc.). Millions of molecules have existed in the universe since before the formation of Earth. Three of them, carbon dioxide, water and oxygen were necessary for the growth of life. Although humanity had always been surrounded by these substances, it has not always known ...
For simple structures, say <10 atoms, it is helpful to depict all atoms explicitly. For more complex molecules, most hydrogen atoms attached to carbon are omitted, and carbon atoms are represented by vertices. For ease of readability, sans-serif fonts are preferred. Many artists employ color to highlight parts of the molecules.
The study of molecules by molecular physics and theoretical chemistry is largely based on quantum mechanics and is essential for the understanding of the chemical bond. The simplest of molecules is the hydrogen molecule-ion, H 2 +, and the simplest of all the chemical bonds is the one-electron bond.
Diatomic molecules consist of a bond between only two atoms. They can be broken into two categories: homonuclear and heteronuclear. A homonuclear diatomic molecule is one composed of two atoms of the same element. Examples are H 2, O 2, and N 2. A heteronuclear diatomic molecule is composed of two atoms of two different elements.
Electron microscopy images of M 3 N@C 80 peapods. Metal atoms (M = Ho or Sc) are seen as dark spots inside the fullerene molecules; they are doubly encapsulated in the C 80 molecules and in the nanotubes. [1] Endohedral fullerenes, also called endofullerenes, are fullerenes that have additional atoms, ions, or clusters enclosed within their ...
In quantum chemistry, the quantum theory of atoms in molecules (QTAIM), sometimes referred to as atoms in molecules (AIM), is a model of molecular and condensed matter electronic systems (such as crystals) in which the principal objects of molecular structure - atoms and bonds - are natural expressions of a system's observable electron density distribution function.