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Apart from 91 Y, 87 Y, and 90 Y, with half-lives of 58.51 days, 79.8 hours, and 64 hours, respectively; all other isotopes have half-lives of less than a day and most of less than an hour. [ 30 ] Yttrium isotopes with mass numbers at or below 88 decay mainly by positron emission (proton → neutron) to form strontium ( Z = 38) isotopes. [ 30 ]
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Group 3 is the first group of transition metals in the periodic table.This group is closely related to the rare-earth elements.It contains the four elements scandium (Sc), yttrium (Y), lutetium (Lu), and lawrencium (Lr).
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.
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs.
Different isotopes of a given element are distinguished by their mass number, which is written as a superscript on the left hand side of the chemical symbol (e.g., 238 U). The mass number is always an integer and has units of "nucleons". Thus, magnesium-24 (24 is the mass number) is an atom with 24 nucleons (12 protons and 12 neutrons).
There were no further discoveries for 30 years, and the element didymium was listed in the periodic table of elements with a molecular mass of 138. In 1879, Delafontaine used the new physical process of optical flame spectroscopy and found several new spectral lines in didymia.
Yttrium and pnictides can form compounds with the chemical formula YE (E = N, P, As, Sb). They can be hydrolyzed in humid air and emit volatile hydrides EH 3. Yttrium and carbon can form a variety of compounds, such as Y 2 C 3, [9] YC 2. [10] They can be made in several ways: 2 Y + 3 C → Y 2 C 3 Y 2 O 3 + 7 C → 2 YC 2 + 3 CO ↑