Atoms and molecules hard

Atoms and Molecules Quiz (Hard)

1. The number of electrons in a neutral atom of an element is equal to:

a) The number of protons b) The number of neutrons c) The atomic number d) The mass number

2. Isotopes of an element have the same number of:

a) Protons b) Electrons c) Neutrons d) Nuclei

3. The term "valency" refers to:

a) The combining capacity of an atom b) The number of electrons in the outermost shell c) The total number of electrons in an atom d) The number of protons and neutrons in the nucleus

4. The concept of "mole" is used to represent:

a) The number of atoms in a molecule b) The mass of a single atom c) The number of molecules in a compound d) The amount of a substance

5. The chemical formula NaCl represents:

a) Sodium chloride b) Nitric acid c) Nitrous oxide d) Nitrogen monoxide

6. The molecular formula of acetic acid is:

a) CH3COOH b) CH3OH c) C6H12O6 d) C6H5OH

7. The chemical formula H2SO4 represents:

a) Sulfur dioxide b) Sulfur trioxide c) Sulfuric acid d) Sodium sulfate

8. The molecular formula of methane is:

a) CH2 b) CH3 c) C2H6 d) C3H8

9. The molecular formula of sulfuric acid is:

a) H2SO3 b) H2S c) H2SO2 d) H2SO4

10. The molecular formula of hydrogen peroxide is:

a) H2O2 b) H2O c) HO2 d) H3O+