📖 what
What is atomic number?
ChemistryPeriodic table
Quick Answer
The atomic number is the number of protons in an atom’s nucleus. It defines which element the atom is.
The Full Story
Atomic number is one of the most important ideas in chemistry because it determines an element’s identity. Hydrogen has atomic number 1, carbon has 6, oxygen has 8, and gold has 79. The modern periodic table is arranged by increasing atomic number, a system established after Henry Moseley’s work in 1913. Because electrons match the proton count in a neutral atom, atomic number also helps predict chemical behavior. If the number of protons changes, the atom becomes a different element entirely.
Key Facts
1.Hydrogen’s atomic number is 1
2.Gold’s atomic number is 79
3.Henry Moseley linked atomic number to the periodic table in 1913
YouTube Angle
Suggested video title for this topic:
"Why one tiny number decides an element’s identity"