Question

give the noble gas abbreviated electron configuration for thallium, element 81, using the orbital (box) method. tl has 1 electrons. the noble gas in brackets represents 2 of the total of 3 core electrons. 4 65 46 57 68

Explanation:

Step1: Determine number of electrons

Thallium (Tl) has an atomic number of 81, so it has 81 electrons.

Step2: Identify noble - gas core

The noble gas before thallium is xenon (Xe) which has 54 electrons. So the noble gas in brackets represents 54 of the total core electrons.

Step3: Write remaining electron configuration

After the [Xe] core, we need to account for the remaining 81 - 54=27 electrons. The electron - filling order gives us the configuration: [Xe]6s$^2$4f$^{14}$5d$^{10}$6p$^{1}$.

• The 6s orbital can hold 2 electrons and is filled first with 2 paired electrons (↑↓).
• The 4f sub - shell has 7 orbitals and can hold 14 electrons. It is completely filled with electrons following Hund's rule (electrons first singly occupy orbitals with parallel spins before pairing up).
• The 5d sub - shell has 5 orbitals and can hold 10 electrons. It is completely filled with electrons following Hund's rule.
• The 6p sub - shell has 3 orbitals and can hold 6 electrons. In thallium, there is 1 electron in the 6p sub - shell, which singly occupies one of the 6p orbitals.

1. 81
2. 54
3. 54
4. Xe
5. s$^2$
6. f$^{14}$
7. d$^{10}$
8. p$^{1}$

Answer:

1. 81
2. 54
3. 54
4. Xe
5. s$^2$
6. f$^{14}$
7. d$^{10}$
8. p$^{1}$