Question

a phosphorus atom combines with 2.5 hydrogen atoms to form a phosphine molecule. why is this inconsistent with dalton’s atomic theory?
○ phosphorus and hydrogen atoms do not combine.
○ atoms of one element cannot change into atoms of another element.
○ atoms combine in 1:1 ratios to form compounds.
○ atoms combine in simple, whole - number ratios to form compounds.

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part c

the formation of a compound often involves the destruction of one or more atoms. why is this inconsistent with dalton’s atomic theory?
○ the formation of a compound often involves the formation of one or more atoms.
○ atoms combine in simple, whole - number ratios to form compounds.
○ in chemical reactions, compounds are neither created nor destroyed.
○ atoms change the way they are bound together when they form a new substance, but they are neither created nor destroyed.

Explanation:

First Question (Phosphine Molecule and Dalton's Theory)

Dalton's atomic theory states that atoms combine in simple, whole - number ratios to form compounds. A ratio of 1 (phosphorus) to 2.5 (hydrogen) is not a simple whole - number ratio.

• The first option is wrong because phosphorus and hydrogen do combine to form phosphine.
• The second option is about atoms not changing into other elements, which is not related to the ratio of combination here.
• The third option is wrong as atoms don't always combine in 1:1 ratios, just simple whole - number ratios.

Dalton's atomic theory states that atoms are neither created nor destroyed in chemical reactions. They just rearrange their bonding.

• The first option is incorrect as it misstates what happens in compound formation.
• The second option is about the ratio of combination, not about the creation or destruction of atoms.
• The third option is wrong because it's atoms (not compounds) that are neither created nor destroyed in chemical reactions.

Answer:

D. Atoms combine in simple, whole - number ratios to form compounds.

Part C (Destruction of Atoms in Compound Formation and Dalton's Theory)