Explore how we represent atoms - from Dalton's simple circles to modern chemical symbols, and understand the concept of atomic mass through an interesting watermelon analogy!
Welcome to Chapter 3.2
Discover the evolution of atomic symbols and the concept of atomic mass
H
Hydrogen
1 FMU
Fruit Mass Unit
Element Colors
Color
Element
Red
Oxygen (O)
White
Hydrogen (H)
Black
Carbon (C)
Explore Atomic Symbols & Mass
Current Lesson Status
Ready to explore the evolution of atomic symbols and the concept of atomic mass!
Modern Chemical Symbols (IUPAC Standards)
Element Name
Symbol
Origin (if applicable)
Hydrogen
H
-
Carbon
C
-
Nitrogen
N
-
Oxygen
O
-
Aluminium
Al
-
Chlorine
Cl
-
Zinc
Zn
-
Cobalt
Co
Note: not CO (carbon monoxide)
Iron
Fe
From Latin: Ferrum
Sodium
Na
From Latin: Natrium
Potassium
K
From German: Kalium
Copper
Cu
From Latin: Cuprum (Cyprus)
Silver
Ag
From Latin: Argentum
Gold
Au
From Latin: Aurum
Remember: The first letter is always uppercase, and the second letter (if present) is always lowercase.
Question 1: Define the atomic mass unit.
One atomic mass unit (u) is defined as exactly one-twelfth (1/12th) the mass of one atom of carbon-12. It was chosen as the standard reference for measuring atomic masses in 1961 by IUPAC.
Question 2: Why is it not possible to see an atom with naked eyes?
Atoms are extremely small, typically around 10^-10 meters in diameter. They are far smaller than the wavelength of visible light (400-700 nanometers), making them impossible to see with the naked eye. Even the most powerful optical microscopes cannot resolve individual atoms.