Write an electron configuration for each ion. a. O^2- b. Br^- c. Sr^2+ d. Co^3+ e. Cu^2+

Name: Problem 25, Chapter 8: Principles of chemistry: A molecular approach
Uploaded: 2020-07-14T22:14:28-08:00
Duration: 4 min 33 s
Channel: Joanna Josey
Description: Write an electron configuration for each ion. a. O^2- b. Br^- c. Sr^2+ d. Co^3+ e. Cu^2+

Write an electron configuration for each ion. a. O^2- b....

Key Concepts

Electron Configuration

This concept describes the distribution of electrons among the various orbitals of an atom. It is written using the notation of principal quantum numbers and subshell letters (s, p, d, f) and is determined by the order in which electron orbitals are filled according to energy levels.

Ions and Their Electron Configurations

When atoms gain or lose electrons, they become ions with either a negative or positive charge, respectively. The electron configuration of an ion is obtained by first writing the configuration for the neutral atom and then either adding electrons (for anions) or removing electrons (for cations), taking into account the order of orbital energies.

Aufbau Principle and Orbital Filling Order

The Aufbau principle explains that electrons occupy orbitals in an order that minimizes the energy of the atom, filling lower energy orbitals first before moving to higher ones. This principle, along with Hund's Rule and the Pauli Exclusion Principle, guides the standard procedure for writing electron configurations for any element or ion.

Electron Removal in Transition Metals

For transition metal ions, the order of electron removal can be atypical compared to the order of orbital filling. Electrons are typically removed from the outermost s orbital before the d orbitals, even though the s orbital is filled prior to the d orbitals in the neutral atom configuration. This nuance is important when determining the accurate electron configuration of transition metal cations.

Transcript

00:01 In this problem, we're being asked to write the electron configuration for a variety of different ions.

00:05 The first one is going to be an o2 minus, so an oxygen ion.

00:12 And so when we're looking at our configuration, we want to figure out where oxygen is first of all, which is right here.

00:20 So from there, we can go ahead and start writing our orbitals.

00:24 So if it was just oxygen, it would be 1s2, and then 2.

00:31 2 because it has, it fills the s orbital there.

00:36 And then it's going to be 2p.

00:39 Now, typically, it'll be 1, 2, 3, 4, 2p4.

00:42 However, because we've gained two more electrons, it's actually going to be 2p6.

00:49 So we could also write it just as neon.

00:54 It has the same configuration as neon.

00:57 For our next one, the next one is bromine 1 minus, and bromine is located right here.

01:11 So again, we can go ahead and start doing our configuration.

01:17 So we would put, oops, wrong one, there we go.

01:21 We would put argon, so we don't have to write out all of those initial s &ps.

01:27 This is period 4, so it would be 4s2, 3d10, because it fills the entire d -shell, and then it would be 1, 2, 3, 4 ,5, 4p5, but because again we've gained one electron, it's going to be 4p6, which is another way of saying it has the same configuration as krypton.

01:58 Next, we have strontium 2 plus.

02:05 So find strontium is right here...

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