Atomic number 25, atomic weight 54.9380. Phosphorus (P): Phosphorus is a poisonous, nonmetallic element that helps protect metal surfaces from corrosion. Atomic number 15, atomic weight 30.9738.

Bainbridge, K. T., Nat. Res. Coun. Preliminary Report No. 1 Science Series (1948). Aston, F. W., Proc. Roy. Soc., A, 163, 391 (1937).

which is based on atomic number rather than atomic mass. This arrangement was established by the British physicist Henry Moseley in 1913, who discovered that the atomic number (the number of ...

The Atomic Mass Data Center and its electronic bulletin are tools for the exchange of information on experimental masses, evaluation of masses, extrapolation of masses, and theoretical masses. One of ...

was less than the atomic mass (average mass of the atom). For example, a helium atom has an atomic mass of 4, but an atomic number (or positive charge) of 2. Since electrons have almost no mass ...

This Q-value calculation programme allows you to calculate reaction Q-values and threshold energies and decay Q values based on the 1995 Update to the Atomic Mass Evaluation and to retrieve other ...

For example, the atomic number of sodium is 11. Every sodium atom has 11 protons and 11 electrons. It has 11 positive charges and 11 negative charges. The mass number of an atom is its total ...

The numbers of subatomic particles in an atom can be calculated from its atomic number and mass number. The periodic table - AQA Mendeleev made an early periodic table. In the modern periodic ...