Predict the ground-state electron configuration of the following ions. write your answers in abbreviated form, that is, beginning with a noble gas in brackets. a). cr2+b.)cu2+c.)co3+

These are three questions and three complete answers

a) Cr²⁺: [Ar] 4s² 3d²

b) Cu²⁺: [Ar] 4s² 3d⁷

c) Co³⁺: [Ar] 4s² 3d⁴

Explanation:

a) Cr²⁺

Z = 24Number of protons: 24Number of elecrons of the neutral atom: 24Charge of the ions: + 2Number of electrons of the ion: 24 - charge = 24 - 2 = 22.Electron configuration:

       Fill the orbitals in increasing order of energy. Using Aufbau's rules the order is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

       Hence, for 22 electrons you get:

       1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d²

Abbreviated notation: since the last complete level is the number 3s² 3p⁶, you use the noble gas of the period 3, which is Ar, and the configuration is:

       

        [Ar] 4s² 3d²

b) Cu²⁺

Z = 29Number of protons: 29Number of elecrons of the neutral atom: 29Charge of the ion: + 2Number of electrons of the ion: 29 - charge = 29 - 2 = 27.Electron configuration:

       Fill the orbitals in increasing order of energy. Using Aufbau's rules the order is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

       Hence, for 27 electrons you get:

       1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷

Abbreviated notation: since the last complete level is the number 3s² 3p⁶, you use the noble gas of the period 3, which is Ar, and the configuration is:

       

        [Ar] 4s² 3d⁷

c) Co³⁺

Z = 27Number of protons: 27Number of elecrons of the neutral atom: 27Charge of the ion: + 3Number of electrons of the ion: 27 - charge = 27 - 3 = 24.Electron configuration:

       Fill the orbitals in increasing order of energy. Using Aufbau's rules the order is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

       Hence, for 24 electrons you get:

       1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁴

Abbreviated notation: since the last complete level is the number 3s² 3p⁶, you use the noble gas of the period 3, which is Ar, and the configuration is:

       

        [Ar] 4s² 3d⁴

; lc

The answer is d.potassium