Question

12 how many neutrons are in the uranium - 235 isotope? (0.5 points) enter your answer 13 how many electrons are in this magnesium ion? (0.5 points)

Explanation:

Step1: Recall uranium - 235 properties

Uranium has an atomic number of 92. The mass number of uranium - 235 is 235. The number of neutrons $n$ is calculated by the formula $n = mass\ number - atomic\ number$.

Step2: Calculate number of neutrons

$n=235 - 92$
$n = 143$

Step3: Recall magnesium ion properties

The atomic number of magnesium (Mg) is 12, which means a neutral magnesium atom has 12 electrons. The given magnesium ion is $Mg^{2 + }$, which has lost 2 electrons.

Step4: Calculate number of electrons in magnesium ion

The number of electrons in $Mg^{2+}$ is $12- 2=10$

Answer:

1. 143
2. 10