Electrochemistry

[Shortcut] Determine no. of paired/ unpaired e– in a species e.g. Te+

← Back to Atomic Structure

Determine total e^– count of the species.
If electron count is less than 18, it is faster to just write out the electronic configuration.
If electron count is more than 18, subtract e^– count by 18, 36 or 54; the largest number that will give you a positive result.
If the remainder is less than or equal to 10, fill them up in d orbitals. Ignore the quantum shell.
If the remainder is more than 10, subtract 10 from the remainder and fill up the leftover e^– in s and p orbitals. Ignore the quantum shell.

Example:

Determine the number of unpaired electrons in (a) Mn²⁺ (b) Cu⁺ (c) Se^– (d) Te⁺.

(a) Mn²⁺: 23e^–

e^– remaining = 23 – 18 = 5

Mn²⁺: […] nd⁵ → 5 unpaired e^–

(b) Mo²⁺ : 40e^–

e^– remaining = 40 – 36 = 4

Mn²⁺: […] nd⁴ → 4 unpaired e^–

e^– remaining = 35 – 18 = 17 (> 10!)

e^– remaining = 17 – 10 = 7

Se^–: […] ns²np⁵→ 1 unpaired e^–

(d) Te⁺: 51e^–

Remaining electrons = 51 - 46 = 5 ns2np3: 3 unpaired electrons

e^– remaining = 51 – 36 = 15 (> 10!)

e^– remaining = 15 – 10 = 5

Te⁺: […] ns²np³→ 3 unpaired e^–

- Writing Electronic Configurations
← Back to Atomic Structure To present the electronic configuration of a species, we need to observe 3 rules/ principles in filling up the atomic orbitals: Lowest energy first (Aufbau Principle) Within each subshell, fill up singly before...

- Titration
← Back to AMS Normal Titration See general approach for chemical calculations. Example: 25.00 cm3 of 0.100 moldm–3 Na2CO3 solution was titrated against 0.200 moldm–3 HCl. Determine the volume of HCl required...

- How To Draw Dot-cross Diagram
← Back to Chemical Bonding 1 Determine the central atom and surrounding atoms. Central atom is commonly the: - Element with the lesser no. of atoms - First element in chemical formula (except H) - Least electronegative...

- Atomic Structure
+ Objectives (a) identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses (b) deduce the behaviour of beams of protons, neutrons and electrons in both electric and magnetic fields (c) describe the distribution...

- Atomic Structure
Learning Objectives (a) identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses (b) deduce the behaviour of beams of protons, neutrons and electrons in both electric and magnetic fields (c) describe...

Electrochemistry