Atomic number

Atomic number is a fundamental concept in chemistry and physics, representing the number of protons found in the nucleus of an atom. It is denoted by the symbol Z.

Definition

The atomic number of an atom is equal to the number of protons in its nucleus. This number is unique for each element and determines the identity of the element. For example, the atomic number of hydrogen is 1, while that of oxygen is 8.

History

The concept of atomic number was first proposed by the British physicist Henry Moseley in 1913. Moseley's work demonstrated that the atomic number is more fundamental than the atomic weight in characterizing the properties of an element.

Significance

The atomic number is crucial in determining the chemical properties of an element. It defines the element's position in the periodic table, and it also determines the number of electrons in a neutral atom, which in turn influences the atom's ability to form chemical bonds.

Determination

The atomic number of an element can be determined using various techniques, such as spectroscopy and mass spectrometry. These methods rely on the unique spectral lines or mass-to-charge ratios associated with each element.

See also

• Isotope
• Atomic mass
• Periodic table
• Chemical element
• Proton