Question

according to john dalton’s observations, when elements combine in a compound, a. the ratio of their masses is always the same. b. each element contributes an equal number of atoms. c. their volumes are always equal. d. their masses are always equal.

Answer 1

Answer:

• The correct answer is a.
• The ratio of their masses is always the same

Explanation:

• Dalton law was based on law of conservation of masses and law of conservation definite proportional. So here , it is cleared that the ratio of their masses should be always same.

Answer 2

According to John Dalton’s observations, when elements combine in a compound,$\boxed{{\text{a}}{\text{. the ratio of their masses is always the same}}}$.

Further explanation:

An element has an atom as the smallest possible particle that it can have. It is also known as the building unit of matter. Atom has a central part called the atomic nucleus.

Postulates of John Dalton’s atomic theory:

1. There are indivisible particles inside every matter. Such particles are called atoms.

2. Atoms are the particles that can neither be produced nor be destroyed.

3. There occurs similarity in the shape and size of atoms of the same element but they are different from the elements of the other elements.

4. Atom is the smallest entity that is involved in the chemical reaction.

5. Atoms of different elements can form compounds after combination with each other. The ratio of combining elements remains fixed, simple and is a whole number.

6. The atoms of the same element have the tendency to form two or more compounds by combining in more than one ratio.

Advantages:

1. The laws of chemical combination are completely explained by this theory.

2. This theory can distinguish between atoms and molecules.

Failures:

1. This theory cannot explain the subdivision of atoms into subatomic particles.

2. Isotopes were nowhere discussed in this theory. These are the atoms of the same element having same atomic number but different mass numbers. Moreover, it did not explain the existence of isobars (atoms of different elements with the same mass number but different atomic numbers).

3. This theory failed to explain the presence of allotropes.

4. The complex organic molecules were not included in this theory.

According to Dalton’s atomic theory, elements combine with each other to form compounds in the same ratio of their masses. Therefore option a is correct.

Learn more:

1. Basis of investigation for the scientists: brainly.com/question/158048

2. Bohr’s model of the atom: brainly.com/question/2965079

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Structure of the atom

Keywords: atom, protons, electrons, neutrons, elements, compounds, subatomic particles, atomic number, mass number, isotope, isobars, Dalton’s atomic theory.