Question

an atomic anion with a charge of - 2 has the following electron configuration:
kr5s²4d¹⁰5p⁶
what is the chemical symbol for the ion?
how many electrons does the ion have?
how many 5p electrons are in the ion?

Explanation:

1. Chemical Symbol of the Ion

Step1: Find electrons in Kr

Krypton (\( \text{Kr} \)) has an atomic number of 36, so it has 36 electrons.

Step2: Calculate electrons from configuration

The electron configuration beyond \( \text{[Kr]} \) is \( 5s^2 4d^{10} 5p^6 \). Calculate the number of electrons here: \( 2 + 10 + 6 = 18 \).

Step3: Total electrons in anion

Total electrons in the anion: \( 36 + 18 = 54 \).

Step4: Find neutral atom's electrons

The anion has a charge of -2, so the neutral atom has \( 54 - 2 = 52 \) electrons (since anion has gained 2 electrons).

Step5: Identify the element

An element with 52 electrons (and protons) is tellurium (\( \text{Te} \)). The anion is \( \text{Te}^{2-} \).

Step1: Electrons in Kr

\( \text{Kr} \) has 36 electrons.

Step2: Electrons from \( 5s^2 4d^{10} 5p^6 \)

Sum: \( 2 + 10 + 6 = 18 \).

Step3: Total electrons

Total: \( 36 + 18 = 54 \).

Step1: Analyze \( 5p^6 \)

The electron configuration has \( 5p^6 \), so the number of \( 5p \) electrons is 6.

Answer:

\( \text{Te}^{2-} \)

2. Number of Electrons in the Ion