Question

The symbol 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

Chemical symbols are abbreviations used in chemistry for chemical elements, functional groups and chemical compounds. Element symbols for chemical elements normally consist of one or two letters from the Latin alphabet and are written with the first letter capitalized.

Complete step by step answer:
As per the question, the students have written the symbols for the given elements. The actual information for the given elements is:
(i) Cobalt: Cobalt is a chemical element with the symbol $Co$ and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron.
(ii) Aluminium: It is a chemical element with the symbol $Al$ and atomic number 13. It is a silvery-white, soft, non-magnetic and ductile metal in the boron group. By mass, aluminium is the most abundant metal in the Earth's crust and the third most abundant element (after oxygen and silicon).
(iii) Helium: It is a chemical element with the symbol $He$ and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table.
(iv) Sodium: Sodium is a chemical element with the symbol $Na$ (from Latin name "natrium") and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table.
Thus, the correct option is C. $He$

So, the correct answer is “Option C”.

Note:
An element is a pure substance which cannot be broken down by chemical means, consisting of atoms which have identical numbers of protons in their atomic nuclei. The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number.