What is the neutron and electron count for a neutral isotope of iridium with a mass number of 191?

To determine the neutron and electron count for a neutral isotope of iridium with a mass number of 191, one must first recognize that the atomic number of iridium is 77. The atomic number, which represents the number of protons in the nucleus, also indicates the number of electrons in a neutral atom. Therefore, for a neutral iridium atom, there will be 77 electrons.

Next, to find the number of neutrons, the mass number (which represents the total number of protons and neutrons in the nucleus) is used. The mass number of iridium is given as 191. The number of neutrons can be calculated by subtracting the atomic number from the mass number:

Neutrons = Mass number - Atomic number

Neutrons = 191 - 77 = 114

This means that a neutral isotope of iridium with a mass number of 191 will have 114 neutrons and 77 electrons. Thus, the correct count for neutrons and electrons in this scenario confirms the neutron count of 114 and the electron count of 77, making this option the accurate choice.