Worksheet Chapter 2: Matter and Atomic Structure

1. True or False: During a pure substance freezing process, the temperature drops rapidly while liquid turns into solid.

2. Fill in the blank: Atoms of the same element with the same proton number but different nucleon numbers are known as ________.

3. Copper consists of two isotopes: 63Cu (69% abundance) and 65Cu (31% abundance). Calculate the relative atomic mass of copper.

4. Sketch/describe the heating curve of solid naphthalene. Explain why the temperature remains constant at the melting point during heating.

5. Magnesium has a proton number of 12. (a) Write the electron arrangement of a neutral magnesium atom. (b) State the number of valence electrons.

6. Which radioisotope is used in agricultural research to trace fertilizer absorption in crops?

7. A neutral atom X has a nucleon number of 39 and contains 20 neutrons. (a) Calculate the proton number of atom X. (b) Write the standard atomic notation for atom X. (c) State the electron arrangement and valence electron count for atom X.

8. True or False: The nucleus of an atom contains almost all of the atom's total mass.

9. State the three subatomic particles in an atom alongside their respective relative electric charges.

10. Compare particles in a solid and a gas in terms of arrangement and movement.