A particular neutral uranium atom has 92 protons, 143 neutrons, and an atomic mass of 235. How many electrons does the atom have?
A. 92
B. 143
C. 235
D. 337
Atoms are neutral. Each electron has a -1 negative charge and each proton has a +1 positive charge. It has 92 protons so it must have ????? electrons.
To determine the number of electrons in a neutral atom, you need to know the atomic number of the element. In this case, the atomic number of uranium is 92, which corresponds to the number of protons in the nucleus.
Since the atom is neutral, it means that the number of protons (+92) is equal to the number of electrons (-92) around the nucleus. Therefore, the correct answer is A. 92.