What makes an element? The number of protons in the nucleus
of an atom is what defines an atom.
To understand spectral lines you have to understand some Atomic Physics.
What makes an element? The number of protons in the nucleus
of an atom is what defines an atom.
For example, Hydrogen (H) atoms have 1 proton ( 
)
and 1 electron ( 
) is ``neutral'' hydrogen ( 
). and and a neutron ( 
) is a ``heavy'' 
of Hydrogen
called deuterium ( 
). is added to Hydrogen, we then have a different element - Helium ( 
).
Q.) How many neutrons in 
?
