00:01
Hi, an atom consists of a nucleus in the center and electrons move around this nucleus in different shells.
00:14
The nucleus consists of protons and neutrons and the electrons are found in these shells.
00:22
Now atomic radius or the atomic size is the distance between the center of the nucleus and the outermost orbit or shell.
00:34
Therefore, atomic size or atomic radius is the shortest distance between the center of nucleus and the outermost shell of the atom.
00:52
Now we need to understand the trend of the atomic size or atomic radius.
00:57
As we move from left to right in a periodic table, this is a periodic table, the atomic radius decreases.
01:06
And as we move from top to bottom in a periodic table, the atomic radius increases.
01:13
This increase is due to the addition of extra shell or the orbit orbital while on moving from left to right, the electrons are added, the number of protons increases but the shell is not added.
01:31
So there is a more pull between the protons and electrons.
01:36
Now we have to compare the atomic radius of the given atoms and or cations.
01:44
We are given mg2 plus cation, magnesium cation, magnesium atom, calcium 2 plus cation or calcium.
01:54
Now we must know that atomic radius of cations are smaller than the atomic radius of atom...