d and s blocks

[torialmquist1F]

Why is the d block written before the s block? Could they be interchangeable or it has to be that way?

[Leon Popa]

As far as my understanding goes,

The s, p, d and f orbitals are ordered on the basis of how many electrons can fit in each orbital. Because s orbitals can only fit 2 electrons, s is written.

p-orbitals can fit 6 electrons total, d-orbitals can fit 10 electrons total, and f-orbitals can fit 14 electrons total.

Therefore, we write p after s, d after p, and f after p. Its a matter of ordering based on increasing numbers of electrons that can fit in each orbital. This eliminates the confusion of writing the orbitals out of order.

Hope that helps,

Best,
- Leon.

[Wenxin Fan 1J]

You write the electron configuration in the order of the principle quantum number "n". The n value of the d sub shell is n-1 compared to the s and the p subshell. Therefore, d is written first.

[204918982]

the energy of (n)s is greater than (n-1)d so you write the d block before the s block. For example: 3d is written before 4s because the energy of 4s is greater than the energy of 3d

[Peter Dis1G]

Most of the time quantum numbers are written in order,except for 2 elements,Cr and Cu.

[AtreyiMitra2L]

D blocks are lower in energy than s blocks when they are filled. For this reason, they are written before.

[Clement Ng]

S blocks are written before d blocks always, unless the n value of s is equal or higher than the n value of d.

[Meredith Steinberg 2E]

You write the electron configuration in order of increasing energy. Since n=3 is lower energy than n=4, 3d is written before 4s even though 4s comes first in the periodic table.

[Navleen Bajwa 3A]

I was confused by this at first too. The d block is listed first before the s block because the d block contains less energy than the s block. The principal quantum number "n" has more energy in comparison to "n-1." Therefore, the 3d would be written before 4s.

[Sarah Brauer]

The d block is lower energy! Also, remember that if you are in the d block the 4th period would be 3d and the 5th period would be 4d

[isauramora3K]

The energy levels go as following (lowest to highest): f, d, s, and p. F is (n-2) and d is (n-1).

[Christy Zhao 1H]

The electronic configuration is written based on the principle quantum number(n), in the order of increasing energy. S blocks have a greater n value than d blocks.

[Dayanara Ruiz]

Simplest Answer: The energy level in the d block is less than the energy level in the d block.

[Karan Singh Lecture 3]

The d block is listed before the s block because it is more stable and represents the flow the of energy.

[Jesus Rodriguez 1J]

The d block is written before the s block because the d block is lower in energy. Since electron configurations are written based on increasing energy d would always come before s.

[Anthony Mercado 1K]

Why is there no energy level after the f block? By having energy levels end at the f block, what is this representative of?

[Steven Luong 1E]

This is because we haven't found any new elements to fit levels after f.