Question

how many protons are in an ion with 54 electrons and a −1 charge?
number of protons:
how many total electrons are in a sr²⁺ ion?
number of electrons:

Explanation:

First Sub - Question: How many protons are in an ion with 54 electrons and a - 1 charge?

Step 1: Recall the charge formula

The charge of an ion is given by the formula: $\text{Charge}=\text{Number of protons}-\text{Number of electrons}$. We can rearrange this formula to solve for the number of protons: $\text{Number of protons}=\text{Charge}+\text{Number of electrons}$.

Step 2: Substitute the given values

We know that the number of electrons is 54 and the charge is - 1. Substituting these values into the formula: $\text{Number of protons}=- 1 + 54$.

Step 3: Calculate the result

$-1 + 54=53$.

Step 1: Find the atomic number of Sr

Strontium (Sr) has an atomic number of 38. The atomic number is equal to the number of protons in a neutral atom, and in a neutral atom, the number of electrons is also equal to the atomic number. So, a neutral Sr atom has 38 electrons.

Step 2: Consider the charge of the ion

A $\ce{Sr^{2+}}$ ion has a + 2 charge. This means that the ion has lost 2 electrons. To find the number of electrons in the ion, we subtract the number of lost electrons from the number of electrons in the neutral atom: $\text{Number of electrons in ion}=\text{Number of electrons in neutral atom}-\text{Charge (magnitude)}$.

Step 3: Substitute the values

Substituting the number of electrons in a neutral Sr atom (38) and the magnitude of the charge (2) into the formula: $\text{Number of electrons in ion}=38 - 2$.

Step 4: Calculate the result

$38-2 = 36$.

Answer:

53

Second Sub - Question: How many total electrons are in a $\ce{Sr^{2+}}$ ion?