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A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the chemical elements.The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behavior of the elements as their atomic number increases: a new row is begun when chemical behavior begins to repeat, meaning that elements with similar behavior fall into ...
The Bohr radius is consequently known as the "atomic unit of length". It is often denoted by a 0 and is approximately 53 pm. Hence, the values of atomic radii given here in picometers can be converted to atomic units by dividing by 53, to the level of accuracy of the data given in this table. Atomic radii up to zinc (30)
A period on the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, elements in the same group (column) have similar chemical and physical properties, reflecting the periodic law.
This nebula is in the western part [4] of the Perseus molecular cloud and is a young region of very active star formation, [6] being one of the best-studied objects of its type. [4] It contains a fairly typical hierarchy of star clusters that are still embedded in the molecular cloud in which they formed, [ 7 ] which are split into two main sub ...
a Group 1 is composed of hydrogen (H) and the alkali metals. Elements of the group have one s-electron in the outer electron shell. Hydrogen is not considered to be an alkali metal as it is not a metal, though it is more analogous to them than any other group. This makes the group somewhat exceptional.
Composite image showing young stars in and around molecular cloud Cepheus B.. This is a list of star-forming regions located in the Milky Way Galaxy and in the Local Group.Star formation occurs in molecular clouds which become unstable to gravitational collapse, and these complexes may contain clusters of young stars and regions of ionized gas called H II regions.
The atomic radius is half of the distance between two nuclei of two atoms. The atomic radius is the distance from the atomic nucleus to the outermost electron orbital in an atom. In general, the atomic radius decreases as we move from left-to-right in a period, and it increases when we go down a group.
The internal structure of a main sequence star depends upon the mass of the star. In stars with masses of 0.3–1.5 solar masses (M ☉), including the Sun, hydrogen-to-helium fusion occurs primarily via proton–proton chains, which do not establish a steep temperature gradient. Thus, radiation dominates in the inner portion of solar mass stars.