why is the electronic configuration of xenom 2,8,18,18,8 and not 2,8,18,25,1
Answers
Xenon is a chemical element with the symbol Xe and atomic number 54. It is a colorless, dense, odorless noble gas found in Earth's atmosphere in trace amounts.[11] Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.[12][13][14]
Xenon, 54Xe
Xenon discharge tube.jpg
A xenon-filled discharge tube glowing light blue
Xenon
Pronunciation
/ˈzɛnɒn/[1]
(ZEN-on)
/ˈziːnɒn/[2]
(ZEE-non)
Appearance
colorless gas, exhibiting a blue glow when placed in an electric field
Standard atomic weight Ar, std(Xe)
131.293(6)[3]
Xenon in the periodic table
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury (element)
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Francium
Radium
Actinium
Thorium
Protactinium
Uranium
Neptunium
Plutonium
Americium
Curium
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
Meitnerium
Darmstadtium
Roentgenium
Copernicium
Nihonium
Flerovium
Moscovium
Livermorium
Tennessine
Oganesson
Kr
↑
Xe
↓
Rn
iodine ← xenon → caesium
Atomic number (Z)
54
Group
group 18 (noble gases)
Period
period 5
Block
p-block
Element category
Noble gas
Electron configuration
[Kr] 4d10 5s2 5p6
Electrons per shell
2, 8, 18, 18, 8
Physical properties
Phase at STP
gas
Melting point
161.40 K (−111.75 °C, −169.15 °F)
Boiling point
165.051 K (−108.099 °C, −162.578 °F)
Density (at STP)
5.894 g/L
when liquid (at b.p.)
2.942 g/cm3[4]
Triple point
161.405 K, 81.77 kPa[5]
Critical point
289.733 K, 5.842 MPa[5]
Heat of fusion
2.27 kJ/mol
Heat of vaporization
12.64 kJ/mol
Molar heat capacity
21.01[6] J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 83 92 103 117 137 165
Atomic properties
Oxidation states
0, +1, +2, +4, +6, +8 (rarely more than 0; a weakly acidic oxide)
Electronegativity
Pauling scale: 2.6
Ionization energies
1st: 1170.4 kJ/mol
2nd: 2046.4 kJ/mol
3rd: 3099.4 kJ/mol
Covalent radius
140±9 pm
Van der Waals radius
216 pm
Color lines in a spectral range
Spectral lines of xenon
Other properties
Natural occurrence
primordial
Crystal structure
face-centered cubic (fcc)Face-centered cubic crystal structure for xenon
Speed of sound
gas: 178 m·s−1
liquid: 1090 m/s
Thermal conductivity
5.65×10−3 W/(m·K)
Magnetic ordering
diamagnetic[7]
Magnetic susceptibility
−43.9·10−6 cm3/mol (298 K)[8]
CAS Number
7440-63-3
History
Discovery and first isolation
William Ramsay and Morris Travers (1898)
Main isotopes of xenon
Isotope Abundance Half-life (t1/2) Decay mode Product
124Xe 0.095% 1.8×1022 y[9] εε 124Te
125Xe syn 16.9 h ε 125I
126Xe 0.089% stable
127Xe syn 36.345 d ε 127I
128Xe 1.910% stable
129Xe 26.401% stable
130Xe 4.071% stable
131Xe 21.232% stable
132Xe 26.909% stable
133Xe syn 5.247 d β− 133Cs
134Xe 10.436% stable
135Xe syn 9.14 h β− 135Cs
136Xe 8.857% 2.165×1021 y[10] β−β− 136Ba
Category Category: Xenon
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Xenon is used in flash lamps[15] and arc lamps,[16] and as a general anesthetic.[17] The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium,[18] and the earliest laser designs used xenon flash lamps as pumps.[19] Xenon is used to search for hypothetical weakly interacting massive particles[20] and as the propellant for ion thrusters in spacecraft.[21]
Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System.[22] Radioactive xenon-135 is produced by beta decay from iodine-135 (a product of nuclear fission), and is the most significant (and unwanted) neutron absorber in nuclear reactors.[23]