What has an atomic mass of 139?
Cesium, isotope of mass 139 | Cs – PubChem.
How many protons neutrons and electrons does lanthanum-139 have?
Diagram of the nuclear composition and electron configuration of an atom of lanthanum-139 (atomic number: 57), the most common isotope of this element. The nucleus consists of 57 protons (red) and 82 neutrons (blue). 57 electrons (green) bind to the nucleus, successively occupying available electron shells (rings).
What is the atomic mass of lanthanum?
57Lanthanum / Atomic number
What element has 139 neutrons?
Lanthanum-139 Information Lanthanum is a silvery metallic element belonging to group 3 of the periodic table and oft considered to be one of the lanthanoids.
When was lanthanum found?
1839Lanthanum / Discovered
Lanthanum was discovered in January 1839 by Carl Gustav Mosander at the Karolinska Institute, Stockholm. He extracted it from cerium which had been discovered in 1803.
How many protons and electrons does Cs+ have?
Cesium Atomic and Orbital Properties
| Atomic Number | 55 |
|---|---|
| Number of Protons | 55 |
| Mass Number | 133 |
| Number of Neutrons | 78 |
| Shell structure (Electrons per energy level) | [2, 8, 18, 18, 8, 1] |
What color is lanthanum?
silvery white
Lanthanum is silvery white, malleable, ductile, and soft enough to be cut with a knife. It is one of the most reactive of the rare-earth metals. It oxidizes rapidly when exposed to air. Cold water attacks lanthanum slowly, while hot water attacks it much more rapidly.
What is the mass of LA 138?
137.907112
Properties of La-138 Isotope:
| Properties of La-138 Isotope: | LA-138 |
|---|---|
| Relative Isotopic Mass | 137.907112 |
| Neutron Number (N) | 81 |
| Atomic Number (Z) | 57 |
| Mass Number (A) | 138 |
What is the atomic number of barium 139?
56
It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ba-139 (Barium, atomic number Z = 56, mass number A = 139).
How many electrons does barium 139 have?
Barium Atomic and Orbital Properties Barium atoms have 56 electrons and the electronic shell structure is [2, 8, 18, 18, 8, 2] with Atomic Term Symbol (Quantum Numbers) 1S0.
What is the mass number of Typical isotopes of lanthanum?
Mass numbers of typical isotopes of Lanthanum are 139. Atomic mass of Lanthanum is 138.9055 u. The atomic mass is the mass of an atom. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to a certain specific isotope of an element.
What is the percent abundance of lanthanum-139 in the atmosphere?
This problem has been solved! The element lanthanum has an atomic weight of 139 and consists of two stable isotopes lanthanum-138 and lanthanum-139. The isotope lanthanum-138 has an atomic mass of 138 amu and a percent natural abundance of 8.90E-2 %. The isotope lanthanum-139 has a percent natural abundance of 99.9 %.
Is lanthanum a rare earth element?
It is also sometimes considered the first element of the 6th-period transition metals and is traditionally counted among the rare earth elements. Lanthanum is a chemical element with atomic number 57 which means there are 57 protons in its nucleus.
Is lanthanum toxic to humans?
Lanthanum has no known biological role. Both the element and its compounds are moderately toxic. Lanthanum is found in ‘rare earth’ minerals, principally monazite (25% lanthanum) and bastnaesite (38% lanthanum).