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A space-filling model of the diatomic molecule dinitrogen, N 2. Diatomic molecules (from Greek di- 'two') are molecules composed of only two atoms, of the same or different chemical elements. If a diatomic molecule consists of two atoms of the same element, such as hydrogen (H 2) or oxygen (O 2), then it is said to be homonuclear.
Pie charts of typical human body composition by percent of mass, and by percent of atomic composition (atomic percent) Body composition may be analyzed in various ways. This can be done in terms of the chemical elements present, or by molecular structure e.g., water , protein , fats (or lipids ), hydroxyapatite (in bones), carbohydrates (such ...
Some compounds may be carcinogenic; some forms are mildly toxic to humans. [11] selenium: 34: 4: Selenium, which is an essential element for animals and prokaryotes and is a beneficial element for many plants, is the least-common of all the elements essential to life.
Some of the largest molecules are macromolecules or supermolecules. The smallest molecule is the diatomic hydrogen (H 2), with a bond length of 0.74 Å. [24] Effective molecular radius is the size a molecule displays in solution. [25] [26] The table of permselectivity for different substances contains examples.
Parts-per-million cube of relative abundance by mass of elements in an average adult human down to 1 ppm. By mass, human cells consist of 65–90% water (H 2 O), and a significant portion of the remainder is composed of carbon-containing organic molecules. Oxygen therefore contributes a majority of a human body's mass, followed by carbon.
In addition to electronic quantum states, molecules have internal degrees of freedom corresponding to rotational and vibrational motion. At appreciable temperatures, many of these new motional modes are excited, resulting in constant motion as seen above. Molecular physics is the study of the physical properties of molecules and molecular dynamics.
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.
Stellar molecules are molecules that exist or form in stars. Such formations can take place when the temperature is low enough for molecules to form – typically around 6,000 K (5,730 °C; 10,340 °F) or cooler. [1] Otherwise the stellar matter is restricted to atoms and ions in the forms of gas or – at very high temperatures – plasma.