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Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and has a high melting point.
A thorium atom has 90 electrons, of which four are valence electrons.Four atomic orbitals are theoretically available for the valence electrons to occupy: 5f, 6d, 7s, and 7p.
This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. For phosphorus (element 15) as an example, the concise form is [Ne] 3s 2 3p 3.
The known isotopes of thorium range in mass number from 207 [11] to 238 ... the isomeric energy is not enough to remove a second electron (thorium's second ...
The number of valence electrons of an element can be determined by the periodic table group (vertical column) in which the element is categorized. In groups 1–12, the group number matches the number of valence electrons; in groups 13–18, the units digit of the group number matches the number of valence electrons. (Helium is the sole ...
This is a list of chemical elements and their atomic properties, ordered by atomic number (Z).. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.
Thorium: Protactinium: Uranium: ... IUPAC group number 18 Name by element: ... Valence electrons are the outermost electrons of an atom and are normally the only ...
There are 32 known isotopes of thorium ranging in mass number from 207 to 238. [57] Of these, ... corresponding to removal of all valence electrons, extends up to ...