When we fill electrons, we have to do according to AUFBAU order but when we need to remove electrons(while writing electronic configuration for ions) we start from outermost shell. Why is this so?

Lithium is a metal whose electronic configuration is 2 and 1 including 3 protons 3 electrons and 3 neutrons. So, if we remove 1 electron from lithium to make it stable. Then ,why would we call it lithium as it has 3 protons 3 electrons and 3 neutrons. But , after removal of 1 electron only 2 electrons are left. So, why would we call it lithium then.

The electronic configuration of calcium is 2,8,8,2.So why we can't write it as 2,8,9,1?

How we can write electronic configuration of subshell and need eg