As - Arsenic

This metaloid has been known for its toxic properties since the 1200's. The arsenite ion, mixed with thiosulfate and acetic acid may be used in a kinetics demonstration in CHM 130 for an abrupt and dramatic color change.

Atomic number - 33 Density g/mL 5 .72

Atomic weight u 74 .9216 Melting point K 1091

Bonding radius A 1 .2 Boiling point K 886

Atomic radius A 1 .33 Heat of vaporization kJ/mol 34 .76

Ionization Potential V 9 .81 Heat of fusion kJ/mol -

Electronegativity - 2 .18 Specific heat J/gK 0 .33

The oxide is mildly acidic.
Crystal are rhombohedral.

Electron config. : [Ar] 3d¹⁰ 4s² 4p³

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra Ac** Rf Db Sg Bh Hs Mt 110 111 112 113

Lanthanides* Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Actinides ** Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Isotopes of As: Click mass number for decay process, product for element page.

065
0.19 sec
EC,9.400 MeV
Ge-65
64.949436 066
0.10 sec
EC,9.800 MeV
Ge-66
65.944368 067
42.5 sec
EC,6.010 MeV
Ge-67
66.939194 068
151.6 sec
EC,8.100 MeV
Ge-68
67.936789 069
15.2 min
EC,4.010 MeV
Ge-69
68.932280 070
52.6 min
EC,6.220 MeV
Ge-70
69.930928 071
65.28 hr
EC,2.013 MeV
Ge-71
70.927113

072
26.0 hr
EC,4.356 MeV
Ge-72
71.926753 073
80.30 da
EC,1.593 MeV
Ge-73
72.923825 074
17.77 da
B-/EC,2.562
Se-74/Ge-74
73.923929 075 100%

Stable

74.921596 076
1.0778 da
B-,2.962 MeV
Se-76
75.922394 077
38.83 hr
B-,2.862 MeV
Se-77
76.920647 078
90.7 min
B-,4.210 MeV
Se-78
77.921828

079
9.01 min
B-,2.281 MeV
Se-79
78.920948 080
15.2 sec
B-,5.641 MeV
Se-80
79.922578 081
33.3 sec
B-,3.856 MeV
Se-81
80.922132 082
19.1 sec
B-,7.270 MeV
Se-82
81.924508 083
13.4 sec
B-,5.460 MeV
Se-83
82.924980 084
4.02 sec
B-/B-n,9.900
Se-84/Se-83
83.929038 085
2.002 sec
B-/B-n,8.900
Se-85/Se-84
84.931829

086
0.945 sec
B-/B-n,11.100
Se-86/Se-85
85.936231 087
0.49 sec
B-/B-n,10.300
Se-87/Se-86
86.939559 MASS abund.
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass

Updated by clh on 2/6/98. This is not a publication of Phoenix College.

Atomic number	-	33		Density	g/mL	5	.72
Atomic weight	u	74	.9216	Melting point	K	1091
Bonding radius	A	1	.2	Boiling point	K	886
Atomic radius	A	1	.33	Heat of vaporization	kJ/mol	34	.76
Ionization Potential	V	9	.81	Heat of fusion	kJ/mol	-
Electronegativity	-	2	.18	Specific heat	J/gK	0	.33
The oxide is mildly acidic.				Crystal are rhombohedral.
Electron config. : [Ar] 3d¹⁰ 4s² 4p³
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065 0.19 sec EC,9.400 MeV Ge-65 64.949436	066 0.10 sec EC,9.800 MeV Ge-66 65.944368	067 42.5 sec EC,6.010 MeV Ge-67 66.939194	068 151.6 sec EC,8.100 MeV Ge-68 67.936789	069 15.2 min EC,4.010 MeV Ge-69 68.932280	070 52.6 min EC,6.220 MeV Ge-70 69.930928	071 65.28 hr EC,2.013 MeV Ge-71 70.927113
072 26.0 hr EC,4.356 MeV Ge-72 71.926753	073 80.30 da EC,1.593 MeV Ge-73 72.923825	074 17.77 da B-/EC,2.562 Se-74/Ge-74 73.923929	075 100% Stable 74.921596	076 1.0778 da B-,2.962 MeV Se-76 75.922394	077 38.83 hr B-,2.862 MeV Se-77 76.920647	078 90.7 min B-,4.210 MeV Se-78 77.921828
079 9.01 min B-,2.281 MeV Se-79 78.920948	080 15.2 sec B-,5.641 MeV Se-80 79.922578	081 33.3 sec B-,3.856 MeV Se-81 80.922132	082 19.1 sec B-,7.270 MeV Se-82 81.924508	083 13.4 sec B-,5.460 MeV Se-83 82.924980	084 4.02 sec B-/B-n,9.900 Se-84/Se-83 83.929038	085 2.002 sec B-/B-n,8.900 Se-85/Se-84 84.931829
086 0.945 sec B-/B-n,11.100 Se-86/Se-85 85.936231	087 0.49 sec B-/B-n,10.300 Se-87/Se-86 86.939559	MASS abund. Halflife Particle, Energy Decay Product(s) Isotopic Mass