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 ...

Because the mass of a proton is equivalent to a neutron, the relative mass of an atom is the same as its ... of a nucleus is the same as its proton (atomic) number. Key fact: isotopes are forms ...

equivalent to the positive charge of the atom) 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 ...

For almost a century, measurements have indicated that a significant proportion of matter in the universe consists of unknown ...

The international team also used the data to get direct information about the deformation of the atomic nucleus in ytterbium ...