| D009502 |
Neutrons |
Electrically neutral elementary particles found in all atomic nuclei except light hydrogen; the mass is equal to that of the proton and electron combined and they are unstable when isolated from the nucleus, undergoing beta decay. Slow, thermal, epithermal, and fast neutrons refer to the energy levels with which the neutrons are ejected from heavier nuclei during their decay. |
Neutron |
|
| D009584 |
Nitrogen |
An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells. |
|
|
| D010100 |
Oxygen |
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration. |
Dioxygen,Oxygen-16,Oxygen 16 |
|
| D002244 |
Carbon |
A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel. |
Carbon-12,Vitreous Carbon,Carbon 12,Carbon, Vitreous |
|
| D005214 |
Fast Neutrons |
Neutrons, the energy of which exceeds some arbitrary level, usually around one million electron volts. |
Fast Neutron,Neutron, Fast,Neutrons, Fast |
|
| D006859 |
Hydrogen |
The first chemical element in the periodic table with atomic symbol H, and atomic number 1. Protium (atomic weight 1) is by far the most common hydrogen isotope. Hydrogen also exists as the stable isotope DEUTERIUM (atomic weight 2) and the radioactive isotope TRITIUM (atomic weight 3). Hydrogen forms into a diatomic molecule at room temperature and appears as a highly flammable colorless and odorless gas. |
Protium,Hydrogen-1 |
|
| D014894 |
Weights and Measures |
Measuring and weighing systems and processes. |
Measures,Scales,Weights,Measure,Measures and Weights |
|