I just want to make sure I'm doing this right...
(Numbers in brackets are the square roots or electrons)
"How many orbitals are completely filled in an atom that has 12 electrons? The electron configuration is 1s[2]2s[2]2p[6]3s[2]?"
It would be 2 right? I'm thinking it takes 1 to fill one, 2 to fill two, and 3 to fill three... Fast help insanely appreciated. :-)
you're correct
To determine the number of completely filled orbitals in an atom, we need to first understand the concept of electron configuration and how electrons fill up orbitals.
The electron configuration is a shorthand notation used to represent the distribution of electrons in an atom's orbitals. Each orbital can hold a maximum of two electrons, with opposite spins. Electrons fill up orbitals in a specific order according to the Aufbau principle, where lower energy orbitals are filled first.
Let's break down the given electron configuration step by step:
1s[2] 2s[2] 2p[6] 3s[2]
In the first shell (n=1), there is one orbital, the 1s orbital. It can hold a maximum of two electrons. Here, the 1s orbital is completely filled with 2 electrons (1s[2]).
Moving to the second shell (n=2), there are three orbitals available – 2s and the set of three 2p orbitals. The 2s orbital can also hold two electrons, and in this case, it is completely filled with 2 electrons (2s[2]). The 2p orbitals can collectively hold a total of six electrons. In this case, the 2p orbitals are completely filled with 6 electrons (2p[6]).
Finally, in the third shell (n=3), the only orbital mentioned is the 3s orbital, which can also hold two electrons. In this case, the 3s orbital is completely filled with 2 electrons (3s[2]).
Now, to find the total number of completely filled orbitals, we add up the number of completely filled orbitals in each shell.
In the first shell, there is 1 completely filled orbital (1s[2]).
In the second shell, there are 4 completely filled orbitals (2s[2] + 2p[6]).
In the third shell, there is 1 completely filled orbital (3s[2]).
Adding these numbers together, we find that there are a total of 6 completely filled orbitals in an atom with 12 electrons.
So the answer is not 2, but rather 6 completely filled orbitals.