00:02
In this question we are trying to write the electron structure for thallium.
00:08
Looking at the periodic table thallium is atomic number 81.
00:14
So it's simple as al, it's atomic number is 81.
00:19
That means as an atom it has 81 protons and therefore 81 electrons as a neutral atom.
00:36
We're told in this question that it forms a cation.
00:40
A cation is a positive ion and cations are formed by a loss of electrons.
00:53
Because if you lose a negative electron what is left is going to have a positive charge.
00:59
So a cation is formed by a loss of one or more electrons.
01:08
So since we are trying to write the electron configuration for thallium with a 1 plus charge that means it has lost one electron to give it that 1 plus charge.
01:28
Okay, so i want to start off just by writing the configuration or the electron structure of a thallium atom and then we'll talk about the correct answer after we get that.
01:38
So following the alfa -bau rule for filling we need to start listing and filling the orbitals in order.
01:44
So we will start with 1s and fill it up followed by 2s and it holds two electrons and then 2p.
01:51
2p there are three of the p orbitals so they hold a total of six electrons.
01:56
Next comes 3s and then 3p which holds six...