Define the atomic mass unit.

– Definition: The atomic mass unit (amu) is a unit used in chemistry to measure the mass of atoms and molecules on a relative scale.

– Relative Scale: Defined as 1/12th of the mass of a neutral carbon-12 atom; allows for easy comparison of masses.

– Approximate Value: 1 amu is roughly equal to the mass of a proton or a neutron, which is approximately 1.67 × 10^-27 kilograms.

– Comparative Use: Enables scientists to compare masses of different atoms and molecules conveniently.

– Representation in Periodic Table: Atomic masses of elements are commonly expressed in atomic mass units (amu).

– Example: For instance, the atomic mass of hydrogen is about 1.008 amu, indicating its mass relative to 1/12th of the mass of a carbon-12 atom.

– Importance: Essential in studying chemical reactions and understanding atomic structures by comparing and analyzing the masses of atoms and molecules.