Is this a multiple choice?
Answer:
smallest is O then Se then K then Cs.
Explanation:
These trends exist. elements tend to get smaller as it completes it's shell since there is more attraction when it is complete. plus the further down the periodic table you go the bigger it is. there are more electrons which repulse each other and make it bigger.
Magic number is any number in electron shells that suggest stability. It corresponds to total number of electrons in filled electron shells.
If an electron is having magic number, then it forms stable bonds.
Explanation:
The magic numbers are 2,10,18,36,54, 86 and 126. This refers to the total number of electrons that an electron can have when it is completely filled.
Atomic nuclei which carries either of these nucleons have high binding energy as compared to others. Hence, they have high stability. Bonds in such elements are more strong.
Radioactive decay of such elements is very slow.
Eugene Winger coined the term "magic number".
1 3/4 Ounces or 1.75 Ounces!
Basically 21/12 = 1.75!
(Mark me as the brainliest if this helps!)
