Calculate the formula mass for the compound nitrous acid.
express your answer using four significant figures.

47.01g/mol

Explanation:

The formula of Nitrous acid is HNO₂:

The formula mass of a compound gives the sum of the atomic masses of the elements that makes up a compound.

Atomic mass of H = 1.0079g/mol

                          N = 14.0067g/mol

                          O = 15.9994g/mol

Formula mass of HNO₂ = 1.0079 +  14.0067 + 2(15.9994)

                                        = 1.0079 +  14.0067 +31.9988

                                         = 47.01g/mol

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

the answer would be c