De combien de fois un atome de soufre est-il plus lourd qu'un atome de carbone ? (2024)

FAQs

How do you find the masse atomique? ›

Atomic number, atomic mass, and relative atomic mass

Forms of the same atom that differ only in their number of neutrons are called isotopes. Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons.

An atom of chlorine-35 contains 18 neutrons (17 protons + 18 neutrons = 35 particles in the nucleus) while an atom of chlorine-37 contains 20 neutrons (17 protons + 20 neutrons = 37 particles in the nucleus). Adding or removing a neutron from an atom's nucleus creates isotopes of a particular element.

The atomic mass unit (AMU or amu) of an element is a measure of its atomic mass. Also known as the dalton (Da) or unified atomic mass unit (u), the AMU expresses both atomic masses and molecular masses.