Question

Elements with filled outermost shells are.
A) $He$
B) $Na$
C) $Ar$
D) Both A and C.

Answer 1

Hint: We know that the electrons within the outermost shell are called valence electrons and therefore the number of electrons it accepts or donates to make a bond is named the valency of an electron. If the outermost shell isn't filled then to fill the outermost shell, it accepts or donates electrons between other atoms.

Complete answer:
We have to know that the helium has atomic number 2 and has an electronic configuration of $1{s^2}$. The electronic configuration of helium clearly shows that the helium has fulfilled electrons in the outermost shell.
In case of sodium, sodium having atomic number 11 and having electronic configuration of $1{s^2}2{s^2}2{p^6}3{s^1}$. The s orbital in sodium is half-filled so therefore, the option B is incorrect.
In case of argon, argon having atomic number 18 and having electronic configuration of $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}$. The electronic configuration of argon clearly shows that the argon has filled electrons in the outermost shell.
The valence shell electronic arrangement of helium and argon is ns2np5. In this way, there are 7 electrons in the peripheral shell of these components. The component passes up the octet arrangement by one electron. Accordingly, these components watch out to either lose one electron and structure a covalent bond or increase one electron and structure an ionic bond. Consequently, these are extremely receptive non-metals.
All the noble gas components will have a totally filled outermost shell. Helium and Argon is a respectable gas, subsequently they have filled the peripheral shell.
Hence option D is correct.

Note:
Now we discuss about the physical properties of halides as,
-Physical state: The components in the group 17 are found in different actual states. For instance, Fluorine and Chlorine are gases. Then again, Bromine is a fluid and Iodine is strong.
-Color: These components have an assortment of tones. For instance, while Fluorine is light yellow in shading, Iodine is dull violet in shading.
-Dissolvability: Fluorine and Chlorine are solvent in water. Then again, Bromine and Iodine are extremely less dissolvable in water.
-Liquefying and breaking points: Softening and breaking points of these components increment as we descend the gathering from Fluorine to Iodine. In this way, Fluorine has the most reduced bubbling and dissolving focuses.