Online Assessment Number 3

1. Most of the mass of an atom is found in the ___________________.

• a. charges

• b. electrons

• c. electrons cloud

• d. nucleus

2. Every atom of the same element has___________________.

• a. the same mass

• b. the same atomic number

• c. same number of neutrons

• d. the same weight of an atom

3. How can atoms acquire a charge?

• a. By gaining or losing electrons

• b. By gaining or losing protons

• c. By gaining or losing neutrons

• d. Atoms cannot acquire a charge

4. The sum of the number of protons and the number of neutrons is known as ____________________.

• a. Atomic mass

• b. Atomic number

• c. Electron

• d. Proton

5. How to compute the number of neutrons of an atom?

• a. Always the same with number of proton

• b. Proton is added to electron of an atom

• c. The difference of atomic mass and atomic number

• d. The product of electron and proton

6. The atomic number tells the _____________________.

• a. number of electrons in the atom

• b. number of protons in the atom

• c. number of neutrons in the atom

• d. number of protons and neutrons

7. The number of protons and neutrons in a nucleus is the____________________.

• a. Atomic mass

• b. Atomic number

• c. Mass number

• d. Nucleons

8. Who was the first to adapt Democritus’ theory into the first modern atomic model?

• a. Ernest Rutherford

• b. John Dalton

• c. Joseph John Thomson

• d. Neil Bohr

9. Which atomic model proposed by J.J Thomson?

• a. Nuclear model

• b. Planetary model

• c. Plum pudding model

• d. Quantum mechanical model

10. How was the plum pudding model different from the hard-sphere model of the atom?

• a. The plum pudding model included negatively charged particles known as electron

• b. The plum pudding model included positively charged particles known as protons

• c. The plum pudding model described electron orbiting a central nucleus

• d. The plum pudding model showed electrons occupying different energy levels