Question

90Sr2+ has:

a) 38 protons, 52 neutrons, and 36 electrons
b) 38 protons, 52 neutrons, and 38 electrons
c) 38 protons, 52 neutrons, and 40 electrons
d) 52 protons, 38 neutrons, and 50 electrons
e) 38 protons, 36 neutrons, and 52 electrons

Answer 1

The isotope 90Sr2+ has 38 protons, 52 neutrons, and 36 electrons since Strontium has an atomic number of 38 and the 2+ charge indicates it has lost two electrons from its neutral state.

Step-by-step explanation:

The symbol 90Sr2+ indicates an isotope of Strontium with a mass number of 90 and a 2+ charge state due to the loss of two electrons. Since the atomic number of Strontium (Sr) is 38, this tells us it has 38 protons. The number of neutrons can be calculated by subtracting the atomic number from the mass number, which is 90 - 38, giving us 52 neutrons. Lastly, because the isotope is a 2+ cation, it has lost two electrons, so it has 38 - 2, resulting in 36 electrons. Therefore, the correct answer is (a) 38 protons, 52 neutrons, and 36 electrons.