Comparing alkali metal properties

Steps:

• Identify the table's properties for lithium (Li) and potassium (K), both Group 1 elements.
• Recall trends: reactivity increases down the group, so K > Li; melting point decreases, so Li > K.
• Match table rows to correct assignments based on periodic trends.
• Select row where both properties align with Li and K characteristics.

Why D is correct:

• Potassium, potassium matches trends where K has higher reactivity and lower melting point than Li, per periodic table laws.

Why the others are wrong:

• A: lithium, lithium incorrectly assigns both to Li, ignoring K's greater reactivity.
• B: potassium, lithium mismatches reactivity (K higher) but melting point (Li higher).
• C: lithium, potassium reverses both, contradicting group trends.

Not enough information: Table details not provided, but assuming standard properties, D fits.

Final answer: D