Isotopes of lawrencium
Encyclopedia
Lawrencium
Lawrencium
Lawrencium is a radioactive synthetic chemical element with the symbol Lr and atomic number 103. In the periodic table of the elements, it is a period 7 d-block element and the last element of actinide series...

(Lr) is an artificial element, and thus a standard atomic mass
Atomic mass
The atomic mass is the mass of a specific isotope, most often expressed in unified atomic mass units. The atomic mass is the total mass of protons, neutrons and electrons in a single atom....

 cannot be given. Like all artificial elements, it has no stable isotope
Stable isotope
Stable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...

s. The first isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

 to be synthesized was 258Lr in 1961. There are eleven known radioisotopes from 252Lr to 262Lr, and 1 isomer
Nuclear isomer
A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons . "Metastable" refers to the fact that these excited states have half-lives more than 100 to 1000 times the half-lives of the other possible excited nuclear states...

 (253mLr). The longest-lived isotope is 262Lr with a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 of 216 minutes. Heavier isotopes are expected to have longer half-lives.

Table

nuclide
symbol
Z(p
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....

)
N(n
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...

)
 
isotopic mass (u)
 
half-life decay
mode(s)Abbreviations:
SF: Spontaneous fission
Spontaneous fission
Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses...

daughter
isotope(s)
nuclear
spin
excitation energy
252LrNot directly synthesized, occurs as a decay product
Decay product
In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...

 of 256Db
103 149 252.09537(27)# 390(90) ms
[0.36(+11-7) s]
α
Alpha decay
Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...

 (90%)
248Md
β+
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...

 (10%)
252No
SF
Spontaneous fission
Spontaneous fission is a form of radioactive decay characteristic of very heavy isotopes. Because the nuclear binding energy reaches a maximum at a nuclear mass greater than about 60 atomic mass units , spontaneous breakdown into smaller nuclei and single particles becomes possible at heavier masses...

(1%)
(various)
253LrNot directly synthesized, occurs as a decay product of 257Db 103 150 253.09521(24)# 580(70) ms
[0.57(+7-6) s]
α (90%) 249Md (7/2-)
SF (9%) (various)
β+ (1%) 253No
253mLr 30(100)# keV 1.5(3) s
[1.5(+3-2) s]
(1/2-)
254LrNot directly synthesized, occurs as a decay product of 258Db 103 151 254.09645(36)# 13(3) s α (78%) 250Md
β+ (22%) 254No
SF (.1%) (various)
255Lr 103 152 255.09668(22)# 22(4) s α (69%) 251Md 7/2-#
β+ (30%) 255No
SF (1%) (various)
256Lr 103 153 256.09863(24)# 27(3) s α (80%) 252Md
β+ (20%) 256No
SF (.01%) (various)
257Lr 103 154 257.09956(22)# 646(25) ms α (99.99%) 253Md 9/2+#
β+ (.01%) 257No
SF (.001%) (various)
258Lr 103 155 258.10181(11)# 4.1(3) s α (95%) 254Md
β+ (5%) 258No
259Lr 103 156 259.10290(8)# 6.2(3) s α (77%) 255Md 9/2+#
SF (23%) (various)
β+ (.5%) 259No
260Lr 103 157 260.10550(12)# 2.7 min α (75%) 256Md
β+ (15%) 260No
SF (10%) (various)
261Lr 103 158 261.10688(22)# 44 min SF (various)
α (rare) 257Md
262Lr 103 159 262.10963(22)# 216 min β+ 262No
α (rare) 258Md

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK