Uranium is a chemical metal element. There are 92 electrons in a single atom.
Every isotope of magnesium has 12 electrons.
If 42 is the atomic number then there is 42 electrons in isotope.
The isotope Cr-54 has 24 electrons.
92
Every isotope of cobalt has 27 electrons.
Seven.
Hafnium has 72 electrons and protons; the number of neutrons is different for each isotope and depend on atomic mass of the isotope.
Isotope U-238 has 92 electrons. This number corresponds to the atomic number of uranium, which is 92.
This question is impossible to answer properly without knowing either how many protons there are or how many neutrons there are or how many electrons there are along with the charge. However it is most likely nitrogen, because Nitrogen's most common isotope is 14.
Protactinium has 91 protons and electrons; the number of neutrons is different for each isotope: Number of neutrons = Atomic Mass of the isotope - 91
Radium has 88 electrons. The number of neutrons is different for each isotope: Number of neutrons = Atomic mass of an isotope - 88
The isotope 210Rn has 86 protons and electrons; also 124 neutrons.