## Midterm Problem

Sara Richmond 2K
Posts: 110
Joined: Fri Aug 30, 2019 12:16 am

### Midterm Problem

Q5C. Calcium ions are important in the process of neurotransmitter release at the neuromuscular junction. Write the full electron-configuration for the ground-state of a
calcium ion.

Ca2+ 2pt

1s2 2s2 2p6 3s2 3p6 2pt

How would we have know to write the electron configuration of calcium 2+? When the problem says ground state should we not right the electron configuration of neutral calcium because it is in it's lowest energy state.

Sara Richmond 2K
Posts: 110
Joined: Fri Aug 30, 2019 12:16 am

### Re: Midterm Problem

Q6.A. Magnesium ions are a known cofactor in over 300 enzymatic reactions.
What are the possible angular momentum quantum numbers of the highest energy
electrons in these magnesium ions? Indicate the corresponding subshell of each angular momentum quantum number.

The electron configuration of Mg is 1s2 2s2 2p6 3s2.
Mg2+ 1s2 2s2 2p6

Again how do we know that we Arte supposed to use Mg2+

Isabel Day 1D
Posts: 48
Joined: Fri Aug 09, 2019 12:15 am

### Re: Midterm Problem

This used to confuse me too. We know we're supposed to use Ca2+ and Mg2+ because these are the most common ions of these elements. Ca and Mg both have 2 valence electrons, so they often donate 2 electrons and become 2+ ions. The question asks for the ground state configuration of the ION and not the element so you have to use Ca2+ and Mg2+.

KHowe_1D
Posts: 103
Joined: Thu Jul 25, 2019 12:15 am
Been upvoted: 1 time

### Re: Midterm Problem

When it asks you to do the Calcium ion it is referring to the most common ion which would be Ca2+. This is apparent when referencing the periodic table because this would be the most stable Calcium ion.

Amir Bayat
Posts: 115
Joined: Sat Sep 07, 2019 12:16 am

### Re: Midterm Problem

The ground state generally refers to the ion that is named. Therefore, when calcium ion is given, we write the electron configuration of Ca 2+. For future problems, typically refer to the ion or atom stated in the question.