00:03
Here in this problem, four ions are given and we have to find out which one is not isoelectonic with krypton.
00:12
Now, what is isoelectonic? isoelectonic species contain the same number of electrons.
00:19
Here, krypton's atomic number is 36, that is it has 36 protons and 36 electrons.
00:29
Now selenium 2 minus atomic number of selenium is 34 that means it has 34 protons and 34 electrons now selenium 2 minus that means selenium has added two more electrons so selenium 2 minus has 36 electrons same as krypton so selenium 2 minus and krypton are is electronics.
01:00
Now, strongtium 2 plus, atomic number of strongtium is 38, so it has 38 protons, 38 electrons, and it is 2 plus, that means it has lost two electrons.
01:14
So now it has 36 electrons.
01:18
So this one is is isoelectonic with krypton.
01:24
Then arsenic 3 plus.
01:28
Arsenic has atomic number of 33.
01:30
That means 33 protons and 33 electrons.
01:35
And it has lost three electrons because it has three plus charge...