Thorium has 90 protons. So for a neutral atom, there has to be 90 electrons. 230 is the total number of nucleons. ie 90 protons and 140 neutrons.
20 electrons
42 electrons
Two electrons from each element are shared; the total is four electrons.
6 valence electrons
3 valence electrons
8 electrons
16 electrons
20 electrons
6 electrons
97 electrons
4 electrons.
4 electrons, 2 valence electrons
Germanium has 32 electrons.
Xenon has 54 electrons.
Argon has 18 electrons.
15 total electrons, 3 valence electrons
Roentgenium has 111 electrons.