Question

Which of the following is/are true regarding hydrogen?

• A. Its mass number is 2 and atomic number is 1
• B. It is also known as inflammable air
• C. It is the smallest and simplest known element
• D. It has only one neutron and one proton

Answer 1

Answer: (B), (C)

The correct options are
B It is also known as inflammable air
C It is the smallest and simplest known element

Hydrogen is also known as inflammable air. It is the only element which has no neutron in its nucleus. It has only one proton and one electron and hence, both atomic number and mass number of hydrogen is 1.