Question

what is the charge of the cr ion that contains 21 electrons? 2- 2+ 3- 3+

Explanation:

Step1: Find the atomic number of Cr

The atomic number of Cr (chromium) is 24. This means a neutral Cr atom has 24 electrons.

Step2: Calculate the charge

The ion has 21 electrons. The charge of an ion is calculated as \( \text{Charge}=\text{Protons}-\text{Electrons} \). Since the number of protons in an atom (and its ion) is equal to the atomic number (24 for Cr), the charge is \( 24 - 21=3 \). A positive charge indicates the loss of electrons.

Answer:

3+