Plot the melting and boiling points of elements Na through Ar on a graph and describe the trends.

• Draw a horizontal axis (x-axis) and label it "Element" or "Atomic Number". Mark points for each element from Na (11) to Ar (18) with equal spacing.
• Draw a vertical axis (y-axis) and label it "Temperature ($^\circ$C)". This axis needs to cover a range from approximately $-200\,^\circ\text{C}$ to $2500\,^\circ\text{C}$. Choose a suitable scale, for example, $1\,\text{cm} = 200\,^\circ\text{C}$, ensuring that both positive and negative temperatures can be plotted.

• For each element, locate its atomic number on the x-axis.
• Plot a point corresponding to its melting point on the y-axis.
  • Na: $(11, 97.8)$
  • Mg: $(12, 650)$
  • Al: $(13, 660.3)$
  • Si: $(14, 1410)$
  • P: $(15, 44.1)$
  • S: $(16, 112.8)$
  • Cl: $(17, -101.5)$
  • Ar: $(18, -189.4)$
• Connect these plotted points with a line.

• For each element, locate its atomic number on the x-axis.
• Plot a point corresponding to its boiling point on the y-axis. Use a different symbol or color for these points.
  • Na: $(11, 882.8)$
  • Mg: $(12, 1091)$
  • Al: $(13, 2470)$
  • Si: $(14, 2355)$
  • P: $(15, 280.5)$
  • S: $(16, 444.6)$
  • Cl: $(17, -34.4)$
  • Ar: $(18, -185.8)$
• Connect these plotted points with a line.

The graph will show two distinct curves:

• Both melting and boiling points generally increase from Na to Al, reaching a peak at Si.
• After Si, both melting and boiling points decrease sharply for P, S, and Cl.
• The lowest melting and boiling points are observed for Ar.

The graph will visually represent the trend of increasing melting/boiling points for metals (Na, Mg, Al), a peak for the giant covalent structure of silicon (Si), and then a sharp drop to very low values for the simple molecular structures of non-metals (P, S, Cl) and the monatomic noble gas (Ar).