The symbol "At" stands for astatine, which is a chemical element in the Periodic Table with the atomic number 85. It is a member of the halogen group and is known to be highly radioactive and rare in nature. Astatine is primarily produced in trace amounts from the decay of heavier elements and has limited applications due to its instability and rarity.
lithium
Carbon
Arsenic
j
The element abbreviation Fe stands for iron.
iron
Chlorine.
Hydrogen
lithium
there is no such element
Nitrogen
Rubidium.
Carbon
Barium
Arsenic
No element has the symbol A
there is no element with the symbol A.