choices are:
Mike is right because the atomic mass of lithium is 6. There are 3 protons and 3 electrons in the atom. 3+3=6
Joan is right because the atomic number of carbon is 6. There are 3 protons and 3 electrons in the atom. The atomic number shows the number of protons plus the number of electrons. 3+3=6
Joan is correct because carbon is a neutral atom. There are the same number of protons and electrons in the atom pictured.
Mike is correct because the atomic number shows the number of protons in all atoms. There are 3 protons and the atomic number of lithium is 3.
Li has atomic no. 3 and mass 7. so the correct ans is Mike is correct because the atomic number shows the number of protons in all atoms. There are 3 protons and the atomic number of lithium is 3.