Question

What element has a symbol $O$?
A) Cobalt
B) Oxygen
C) Osmium
D) Carbon

Answer 1

Hint: We have to remember that the atomic symbol represents the atomic element that is present on the periodic table. Periodic tables are composed of certain groups and periods. And the element having atomic symbol \[O\] belongs to the group $16$ in a periodic table. Losing and gaining of electrons describes the charges on a particular element or an atom.

Complete answer:
Option A) this is an incorrect option as cobalt has an atomic symbol \[Co\] having atomic number $27$.
It is a transition metal and this element belongs to d block elements.
Electronic configuration of \[Co\]: \[\left[ {Ar} \right]3{d^7}4{s^2}\]
Option B) This is a correct option as \[O\] this symbol is an atomic symbol of oxygen having atomic number 8. It belongs to group 16 in a periodic table.
Electronic configuration of\[O\]: \[1{s^2}2{s^2}2{p^4}\]
\[O\] has $2$ electrons less to complete its octet or to attain stable noble gas configuration. Oxygen gas is odorless and colorless gas. Oxygen on reaction with hydrogen gives water. It is present in $21\% $ in earth’s atmosphere. The most common oxidation state of oxygen is $ - 1$ and $ - 2$.
Oxygen also has isotopes i.e. \[O{\;^{16}}O{,^{17}}O{,^{18}}\].
Option C) this is an incorrect option as Osmium has an atomic symbol \[Os\]. It has an atomic number $76$. It belongs to the group $8$.
Electronic configuration of \[Os\] : \[\left[ {Xe} \right]4{f^{14}}5{d^6}4{s^2}\]
Option D) this is an incorrect option as Carbon has an atomic symbol $C$. It has an atomic number $6$.
Electronic configuration of C: \[1{s^2}2{s^2}2{p^2}\]

Note:
We have to remember that oxygen is an element having the atomic symbol \[O\] it is a colorless and odorless gas i.e. present in $21\% $ in Earth’s atmosphere. As we know that the noble gases have stable electronic configuration that means its octet is completely filled and they are stable amongst all elements.