Question

The symbol of the elements of the elements cobalt, aluminium, helium and sodium respectively written by the student are as follows. Which symbol is the correct one?
(A) CO
(B) AL
(C) He
(D) SO

Answer 1

Hint: Chemical symbols are abbreviations used for functional groups, chemical elements etc. Element symbol for chemical elements usually consists of two letters. While naming the elements with two letters, the first letter is capital and the second one is small.

Complete Step by step solution:
Cobalt: It is a chemical element with atomic number 27. It is found in the earth's crust only in combined form and it is a ferromagnetic metal. Cobalt is used in the production of high-performance alloys. It can also be used to make rechargeable batteries. Also, several cobalt compounds are catalysts in oxidation reactions. The symbol of cobalt is Co.
Aluminum: It is an element with atomic number 13. It is soft and a nonmagnetic and ductile metal. Aluminium is the most abundant metal in the earth's crust. It is highly reactive and it is known for its low density and ability to resist corrosion. The major uses for aluminium metal are in transportation, packaging etc. Its symbol is Al.
Helium: It is an element with atomic number 2. It is colorless, odorless, tasteless gas with inert nature. Its boiling point is lowest among others and it is the second lightest element. Helium is used as a carrier gas for gas chromatography. Its symbol is He.
Sodium: It is an element with atomic number 11 and it is also highly reactive. It is an alkali metal as it belongs to group 1 of periodic table. It is an essential element for all animals and some plants. It has the symbol Na.
Hence, the correct answer is He that is option C.

Note:
An element consists of atoms and it is a pure substance. Atoms in the element have the same number of protons in their respective atomic nuclei. The atomic mass of an element is equal to the sum of the number of protons and neutrons present in the nucleus.