Question

Which of the following statements is one of the postulates in Dalton’s atomic theory?

1.) Atoms of different elements can chemically combine in any ratio, including fractions, to form compounds.
2.) Atoms of different elements can chemically combine in whole-number ratios.
3.) Atoms of different elements cannot physically mix together.
4.)Atoms of different elements cannot be chemically or physically combined in any way.

Answer 1

The statement aligning with Dalton's atomic theory is that atoms of different elements combine in whole-number ratios. This reflects one of the foundational aspects of the theory, which also includes that all matter comprises indivisible atoms and that atoms of the same element are identical.

Step-by-step explanation:

The correct statement from those provided that is one of the postulates in Dalton's atomic theory is:

2.) Atoms of different elements can chemically combine in whole-number ratios.

This reflects the historical postulate proposed by John Dalton in 1804 as part of his atomic theory. According to Dalton, different elements have unique types of atoms, and when these atoms combine to form compounds, they do so in simple whole-number ratios, known as definite proportions.

His theory also stated that:

• All matter is composed of atoms.
• Atoms of the same element are identical in size, mass, and other properties, but differ from atoms of other elements.
• In chemical reactions, atoms are rearranged, combined, or separated but not created or destroyed.

While Dalton's atomic theory laid the groundwork for modern chemistry, it does not explain complex organic compounds which may appear to have fractional atomic ratios or the presence of allotropes—different structural forms of the same element that exhibit different properties, like charcoal, graphite, and diamond.