Atomic number 12 how many electrons
Finding the atomic number on the Periodic Table gives not only the number of protons but also the number of electrons in a neutral atom or isotope. In an unbalanced atom or isotope, the number of protons doesn't equal the number of electrons.As magnesium has atomic number 12 it's electronic configuration is 2, 8, 2 in the K, L, M shells. Thus as we can see it has 2 electrons in the outermost shell hence, it has 2 valence electrons. atomic number 12 how many electrons
The number of neutrons is equal to the Atomic Mass minus the Atomic Number. So for your question, the Periodic Table tells us that carbon has an Atomic Number of 6, so there are 6 protons and 6 electrons.