Gadolinium – Protons – Neutrons – Electrons – Electron Configuration

Gadolinium-protons-neutrons-electrons-configuration

Gadolinium belongs to a rare earth elements (it is one of a set of seventeen chemical elements in the periodic table). In nuclear industry gadolinium is commonly used as a neutron absorber due to very high neutron absorbtion cross-section of two isotopes 155Gd and 157Gd. Gadolinium is widely used as a burnable absorber, which is commonly used in fresh fuel to compensate an excess of reactivity of reactor core. Gadolinium is produced both from monazite and bastnäsite. Commercially, it is recovered from monazite sand and bastnasite by extraction processes and ion exchange techniques.

Protons and Neutrons in Gadolinium

Proton Number - Atomic NumberGadolinium is a chemical element with atomic number 64 which means there are 64 protons in its nucleus. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10-19 coulombs.

The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N – Z = A – 2Z.

For stable elements, there is usually a variety of stable isotopes. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. Mass numbers of typical isotopes of Gadolinium are 154-160.

Main Isotopes of Gadolinium

Gadolinium occurs in 6 natural isotopes: 154Gd, 155Gd, 156Gd. 157Gd, 158Gd and 160Gd. 158Gd is the most common isotope, having a natural abundance of approximately 24%.

Gadolinium-154 is composed of 64 protons, 90 neutrons, and 64 electrons.

Gadolinium-155 is composed of 64 protons, 94 neutrons, and 64 electrons.

Gadolinium-156 is composed of 64 protons, 92 neutrons, and 64 electrons.

Gadolinium-157 is composed of 64 protons, 93 neutrons, and 64 electrons.

Gadolinium-158 is composed of 64 protons, 94 neutrons, and 64 electrons.

Gadolinium-160 is composed of 64 protons, 96 neutrons, and 64 electrons.

Stable Isotopes

Isotope Abundance Neutron Number
154Gd 2.18% 90
155Gd  14.80% 91
156Gd  20.47% 92
157Gd  15.65% 93
158Gd  24.84% 94
160Gd  21.86% 96

Typical Unstable Isotopes

Isotope Half-life Decay Mode Product
148Gd 75 y alpha decay 144Sm
150Gd 1.8×106 y alpha decay 146Sm
152Gd 1.08×1014 y alpha decay 148Sm

Electrons and Electron Configuration

The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. Therefore, the number of electrons in neutral atom of Gadolinium is 64. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom.

Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, the atomic number identifies the various chemical elements. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.

Electron configuration of Gadolinium is [Xe] 4f7 5d1 6s2.

Possible oxidation states are +3.

Like most of the rare earths, gadolinium forms trivalent ions with fluorescent properties, and salts of gadolinium(III) are used as phosphors in various applications.

The kinds of gadolinium(III) ions occurring in water-soluble salts are toxic to mammals. However, chelated gadolinium(III) compounds are far less toxic because they carry gadolinium(III) through the kidneys and out of the body before the free ion can be released into the tissues.

Most Common Chemical Compound of Gadolinium

Gadolinium(III) oxide (archaically gadolinia) is an inorganic compound with the formula Gd2O3. It is one of the most commonly available forms of the rare-earth element gadolinium, derivatives of which are potential contrast agents for magnetic resonance imaging.

About Protons

protonA proton is one of the subatomic particles that make up matter. In the universe, protons are abundant, making up about half of all visible matter. It has a positive electric charge (+1e) and a rest mass equal to 1.67262 × 10−27 kg (938.272 MeV/c2)— marginally lighter than that of the neutron but nearly 1836 times greater than that of the electron. The proton has a mean square radius of about 0.87 × 10−15 m, or 0.87 fm, and it is a spin – ½ fermion.

The protons exist in the nuclei of typical atoms, along with their neutral counterparts, the neutrons. Neutrons and protons, commonly called nucleons, are bound together in the atomic nucleus, where they account for 99.9 percent of the atom’s mass. Research in high-energy particle physics in the 20th century revealed that neither the neutron nor the proton is not the smallest building block of matter.

About Neutrons

A neutron is one of the subatomic particles that make up matter. In the universe, neutrons are abundant, making up more than half of all visible matter. It has no electric charge and a rest mass equal to 1.67493 × 10−27 kg—marginally greater than that of the proton but nearly 1839 times greater than that of the electron. The neutron has a mean square radius of about 0.8×10−15 m, or 0.8 fm, and it is a spin-½ fermion.

Atomic nuclei consist of protons and neutrons, which attract each other through the nuclear force, while protons repel each other via the electric force due to their positive charge. These two forces compete, leading to various stability of nuclei. There are only certain combinations of neutrons and protons, which forms stable nuclei.

Neutrons stabilize the nucleus, because they attract each other and protons , which helps offset the electrical repulsion between protons. As a result, as the number of protons increases, an increasing ratio of neutrons to protons is needed to form a stable nucleus. If there are too many or too few neutrons for a given number of protons, the resulting nucleus is not stable and it undergoes radioactive decayUnstable isotopes decay through various radioactive decay pathways, most commonly alpha decay, beta decay, or electron capture. Many other rare types of decay, such as spontaneous fission or neutron emission are known. It should be noted that all of these decay pathways may be accompanied by the subsequent emission of gamma radiation. Pure alpha or beta decays are very rare.

About Electrons and Electron Configuration

The periodic table is a tabular display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and chemical properties. The electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. Knowledge of the electron configuration of different atoms is useful in understanding the structure of the periodic table of elements.

Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. The chemical properties of the atom are determined by the number of protons, in fact, by number and arrangement of electrons. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.

It is the Pauli exclusion principle that requires the electrons in an atom to occupy different energy levels instead of them all condensing in the ground state. The ordering of the electrons in the ground state of multielectron atoms, starts with the lowest energy state (ground state) and moves progressively from there up the energy scale until each of the atom’s electrons has been assigned a unique set of quantum numbers. This fact has key implications for the building up of the periodic table of elements.

electron configuration - blocks - elementsThe first two columns on the left side of the periodic table are where the s subshells are being occupied. Because of this, the first two rows of the periodic table are labeled the s block. Similarly, the p block are the right-most six columns of the periodic table, the d block is the middle 10 columns of the periodic table, while the f block is the 14-column section that is normally depicted as detached from the main body of the periodic table. It could be part of the main body, but then the periodic table would be rather long and cumbersome.

For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. The electron configuration can be visualized as the core electrons, equivalent to the noble gas of the preceding period, and the valence electrons (e.g. [Xe] 6s2 for barium).

Oxidation States

Oxidation states are typically represented by integers which may be positive, zero, or negative. Most elements have more than one possible oxidation state. For example, carbon has nine possible integer oxidation states from −4 to +4.

The current IUPAC Gold Book definition of oxidation state is:

“Oxidation state of an atom is the charge of this atom after ionic approximation of its heteronuclear bonds…”

and the term oxidation number is nearly synonymous. An element that is not combined with any other different elements has an oxidation state of 0. Oxidation state 0 occurs for all elements – it is simply the element in its elemental form. An atom of an element in a compound will have a positive oxidation state if it has had electrons removed. Similarly, adding electrons results in a negative oxidation state. We have also distinguish between the possible and common oxidation states of every element. For example, silicon has nine possible integer oxidation states from −4 to +4, but only -4, 0 and +4 are common oxidation states.

Summary

Element Gadolinium
Number of protons 64
Number of neutrons (typical isotopes) 154-160
Number of electrons 64
Electron configuration [Xe] 4f7 5d1 6s2
Oxidation states +3

Gadolinium-periodic-table

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Properties of other elements

Gadolinium - Comparison of Protons - Neutrons and Electrons

Periodic Table in 8K resolution

Other properties of Gadolinium