Question

SEP Develop Models Each helium atom has two protons. Sketch models
of helium-3 and helium-4, which have approximate masses of 3 amu
and 4 amu, respectively. Label and differentiate protons, neutrons, and
electrons in your models?

Answer 1

Protons and neutrons are located in the nucleus of the atom while the electrons move in the trajectory of the shell

Further explanation  

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.  

So Isotopes are elements that have the same Atomic Number (Proton)  

Isotopes of Helium : helium-3 and helium-4

• ₂³He :

protons = 2

electrons=protons=2

neutron=mass number-atomic number=3-2=1

• ₂³He :

protons = 2

electrons=protons=2

neutron=mass number-atomic number=3-2=1

• ₂⁴He

protons = 2

electrons=protons=2

neutron=mass number-atomic number=4-2=2

Protons and neutron in the nucleus, electrons in the shell