The atomic number belongs to an atom of a specific element.
The atomic number is a fundamental property of a chemical element. It is the number of protons found in the nucleus of every atom of that element. Since atoms are electrically neutral, the atomic number also equals the number of electrons surrounding the nucleus of a neutral atom of that element.
For example:
- Hydrogen (H) has an atomic number of 1 because each hydrogen atom has 1 proton.
- Oxygen (O) has an atomic number of 8 because each oxygen atom has 8 protons.
- Sodium (Na) has an atomic number of 11 because each sodium atom has 11 protons.
The atomic number uniquely identifies an element. It's essentially the element's "serial number". Elements are arranged on the periodic table in order of increasing atomic number.
In summary, the atomic number describes a fundamental characteristic of any specific element's atoms. It defines whose atoms are being described by detailing the number of protons contained within those atoms.
