Hydrogen
Hydrogen has a mass number of one and an atomic number of one.
Hydrogen atoms, therefore, contain only one proton and one electron.
No neutrons? No wonder they’re so light!
NOTE:
As shown above, hydrogen has no neutrons.
The number of protons defines an element, because it’s the only thing that remains constant; everything else can change.
Electrons can be transferred from one atom to another through ionic bonding to make ions (remember the transfer being ironed onto the t-shirt?) and the number of neutrons can also be altered to form an isotope (‘ice on top’).
It is the number of protons that defines the name of the atom.
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