Periodic Table Element Comparison: Compare Elements - Helium vs Americium
Compare Helium and Americium on the basis of their properties, attributes and periodic table facts. Compare elements on more than 90 properties. All the elements of similar categories show a lot of similarities and differences in their chemical, atomic, physical properties and uses. These similarities and dissimilarities should be known while we study periodic table elements. You can study the detailed comparison between Helium vs Americium with most reliable information about their properties, attributes, facts, uses etc. You can compare He vs Am on more than 90 properties like electronegativity , oxidation state, atomic shells, orbital structure, Electronaffinity, physical states, electrical conductivity and many more. Helium and Americium comparison table on more than 90 properties.
Helium and Americium Comparison
Facts
| Name | Helium | Americium |
|---|---|---|
| Atomic Number | 2 | 95 |
| Atomic Symbol | He | Am |
| Atomic Weight | 4.002602 | 243 |
| Phase at STP | Gas | Solid |
| Color | Colorless | Silver |
| Metallic Classification | Noble Gas | Actinide |
| Group in Periodic Table | group 18 | group - |
| Group Name | helium family or neon family | |
| Period in Periodic Table | period 1 | period 7 |
| Block in Periodic Table | p -block | f -block |
| Electronic Configuration | 1s2 | [Rn] 5f7 7s2 |
| Electronic Shell Structure (Electrons per shell) | 2 | 2, 8, 18, 32, 25, 8, 2 |
| Melting Point | 0 K | 1449 K |
| Boiling Point | 4.22 K | 2284 K |
| CAS Number | CAS7440-59-7 | CAS7440-35-9 |
| Neighborhood Elements | Neighborhood Elements of Helium | Neighborhood Elements of Americium |
History
| Parameter | Helium | Americium |
|---|---|---|
| History | The element Helium was discovered by P. Janssen and N. Lockyer in year 1868 in Sweden and United Kingdom. Helium derived its name from the Greek word helios, meaning 'sun'. | The element Americium was discovered by G. T. Seaborg,R. A. James,O. Morgan and A. Ghiorso in year 1944 in United States. Americium derived its name from The Americas, as the element was first synthesized on the continent, by analogy with europium. |
| Discovery | P. Janssen and N. Lockyer (1868) | G. T. Seaborg,R. A. James,O. Morgan and A. Ghiorso (1944) |
| Isolated | W. Ramsay,T. Cleve, and N. Langlet (1895) | () |
Presence: Abundance in Nature and Around Us
Parts per billion (ppb) by weight / by atoms (1ppb =10^-7 %)
| Property | Helium | Americium |
|---|---|---|
| Abundance in Universe | 230000000 / 72000000 | - / - |
| Abundance in Sun | 230000000 / 74000000 | - / - |
| Abundance in Meteorites | - / - | - / - |
| Abundance in Earth's Crust | 5.5 / 30 | - / - |
| Abundance in Oceans | 0.0072 / 0.011 | - / - |
| Abundance in Humans | - / - | - / - |
Crystal Structure and Atomic Structure
| Property | Helium | Americium |
|---|---|---|
| Atomic Volume | 22.4136 cm3/mol | 17.63 cm3/mol |
| Atomic Radius | 31 pm | 175 pm |
| Covalent Radius | 32 pm | - |
| Van der Waals Radius | 140 pm | - |
Atomic Spectrum - Spectral Lines | ||
| Emission Spectrum |  |  |
| Absorption Spectrum |  |  |
| Lattice Constant | 424.2, 424.2, 424.2 pm | 346.81, 346.81, 1124.1 pm |
| Lattice Angle | π/2, π/2, π/2 | π/2, π/2, 2 π/3 |
| Space Group Name | Fm_ 3m | P63/mmc |
| Space Group Number | 225 | 194 |
| Crystal Structure | Face Centered Cubic  | Simple Hexagonal  |
Atomic and Orbital Properties
| Property | Helium | Americium |
|---|---|---|
| Atomic Number | 2 | 95 |
| Number of Electrons (with no charge) | 2 | 95 |
| Number of Protons | 2 | 95 |
| Mass Number | 4.002602 | 243 |
| Number of Neutrons | 2 | 148 |
| Shell structure (Electrons per energy level) | 2 | 2, 8, 18, 32, 25, 8, 2 |
| Electron Configuration | 1s2 | [Rn] 5f7 7s2 |
| Valence Electrons | 1s2 | 5f7 7s2 |
| Oxidation State | - | 3 |
| Atomic Term Symbol (Quantum Numbers) | 1S0 | 8S7/2 |
| Shell structure |  |  |
Isotopes and Nuclear Properties
Helium has 2 stable naturally occuring isotopes while Americium has 0 stable naturally occuring isotopes.
| Parameter | Helium | Americium |
|---|---|---|
| Known Isotopes | 3He, 4He, 5He, 6He, 7He, 8He, 9He, 10He | 231Am, 232Am, 233Am, 234Am, 235Am, 236Am, 237Am, 238Am, 239Am, 240Am, 241Am, 242Am, 243Am, 244Am, 245Am, 246Am, 247Am, 248Am, 249Am |
| Stable Isotopes | Naturally occurring stable isotopes: 3He, 4He | |
| Neutron Cross Section | 0.007 | 74 |
| Neutron Mass Absorption | 0.00001 | - |
Chemical Properties: Ionization Energies and electron affinity
| Property | Helium | Americium |
|---|---|---|
| Valence or Valency | 0 | 4 |
| Electronegativity | - | 1.13 Pauling Scale |
| Electron Affinity | 0 kJ/mol | - |
| Ionization Energies | 1st: 2372.3 kJ/mol 2nd: 5250.5 kJ/mol | 1st: 578 kJ/mol |
Physical Properties
| Property | Helium | Americium |
|---|---|---|
| Density | 0.0001785 g/cm3 | 13.67 g/cm3 |
| Molar Volume | 22.4136 cm3/mol | 17.63 cm3/mol |
Elastic Properties | ||
| Young Modulus | - | - |
| Shear Modulus | - | - |
| Bulk Modulus | - | - |
| Poisson Ratio | - | - |
Hardness - Tests to Measure of Hardness of Element | ||
| Mohs Hardness | - | - |
| Vickers Hardness | - | - |
| Brinell Hardness | - | - |
Electrical Properties | ||
| Electrical Conductivity | - | - |
| Resistivity | - | - |
| Superconducting Point | - | 0.6 |
Heat and Conduction Properties | ||
| Thermal Conductivity | 0.1513 W/(m K) | 10 W/(m K) |
| Thermal Expansion | - | - |
Magnetic Properties | ||
| Magnetic Type | Diamagnetic | Paramagnetic |
| Curie Point | - | - |
| Mass Magnetic Susceptibility | -5.9e-9 m3/kg | 5.15e-8 m3/kg |
| Molar Magnetic Susceptibility | -2.36e-11 m3/mol | 1.251e-8 m3/mol |
| Volume Magnetic Susceptibility | -1.05e-9 | 0.000704 |
Optical Properties | ||
| Refractive Index | 1.000035 | - |
Acoustic Properties | ||
| Speed of Sound | 970 m/s | - |
Thermal Properties - Enthalpies and thermodynamics
| Property | Helium | Americium |
|---|---|---|
| Melting Point | 0 K | 1449 K |
| Boiling Point | 4.22 K | 2284 K |
| Critical Temperature | 5.19 K | - |
| Superconducting Point | - | 0.6 |
Enthalpies | ||
| Heat of Fusion | 0.02 kJ/mol | - |
| Heat of Vaporization | 0.083 kJ/mol | - |
| Heat of Combustion | - | - |
Regulatory and Health - Health and Safety Parameters and Guidelines
| Parameter | Helium | Americium |
|---|---|---|
| CAS Number | CAS7440-59-7 | CAS7440-35-9 |
| RTECS Number | RTECSMH6520000 | - |
| DOT Hazard Class | 2.2 | - |
| DOT Numbers | 1963 | - |
| EU Number | - | - |
| NFPA Fire Rating | 0 | - |
| NFPA Health Rating | 1 | - |
| NFPA Reactivity Rating | 0 | - |
| NFPA Hazards | - | - |
| AutoIgnition Point | - | - |
| Flashpoint | - | - |
Compare With Other Elements
Compare Helium and Americium with other elements of the periodic table.