00:01
Okay, so in general, the rules for writing out electron configurations apply to every atom.
00:08
Except there are two main exceptions in chromium and copper.
00:15
So chromium, start with that, has the atomic number of 24.
00:22
So we can use, if we use the shorthand, we can look at argon, and we know that that is a full, failant shell.
00:34
That represents 18 electrons.
00:38
Okay, so argonne will be 1s2, 2s2, 2p6, 3s2 3p6.
00:48
From there, 24 minus 18, we need to account for 6 electrons.
00:54
So according to the normal rules, we would say 4s2, 3d4.
01:05
That is not what it actually is.
01:09
So what it actually is is 4s1 3d5.
01:18
And the reason is since the 3d orbital is higher energy, we want it to be more stable.
01:29
And it is more stable when they're, instead of having four electrons and having one in each of the five sub -shells and then having one in each of the five subshells and then having one...