Question

1. where does the name atom come from? 2. what were daltons five postulates? a. b. c. d. e. 3. what was the first subatomic particle to be discovered? a. who discovered it? b. what experiment was used to discover it? c. what is its charge? d. where is it located? e. what atomic model was used at the time? 4. what was the second subatomic particle to be discovered? a. who discovered it? b. what experiment was used to discover it? c. what is its charge? d. where is it located? e. what atomic model was used at the time? 5. what was the third subatomic particle to be discovered? a. who discovered it? b. what experiment was used to discover it? c. what is its charge? d. where is it located? e. what atomic model was used at the time?

Explanation:

1. The word "atom" comes from the Greek word "atomos", which means indivisible. Ancient Greek philosophers like Democritus proposed the concept of atoms as the smallest - indivisible units of matter.
2. Dalton's five postulates:

• a. Elements are composed of extremely small particles called atoms.
• b. All atoms of a given element are identical, having the same size, mass, and chemical properties. Atoms of different elements are different in these respects.
• c. Compounds are composed of atoms of more than one element. In any compound, the ratio of the numbers of atoms of any two of the elements present is either an integer or a simple fraction.
• d. A chemical reaction involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction.
• e. Atoms are indestructible and retain their identity in chemical reactions.

1. The first sub - atomic particle to be discovered was the electron.

• a. J. J. Thomson discovered the electron.
• b. He used the cathode - ray tube experiment to discover it.
• c. The electron has a negative charge.
• d. It is located outside the nucleus in the electron cloud.
• e. The plum - pudding model was used at the time, which envisioned the atom as a uniform positive sphere with electrons embedded in it like plums in a pudding.

1. The second sub - atomic particle to be discovered was the proton.

• a. Ernest Rutherford is credited with the discovery of the proton.
• b. His gold - foil experiment led to the understanding of the nucleus, and subsequent work identified the proton.
• c. The proton has a positive charge.
• d. It is located in the nucleus of the atom.
• e. The nuclear model of the atom, with a small, dense, positively - charged nucleus surrounded by electrons, was in use at the time.

1. The third sub - atomic particle to be discovered was the neutron.

• a. James Chadwick discovered the neutron.
• b. He used an experiment involving beryllium radiation to discover it.
• c. The neutron has no charge (it is neutral).
• d. It is located in the nucleus of the atom.
• e. The Bohr - Rutherford model was refined to include neutrons in the nucleus.

Answer:

1. The word "atom" comes from the Greek word "atomos" meaning indivisible.

2.

• a. Elements are composed of atoms.
• b. All atoms of a given element are identical.
• c. Compounds are composed of atoms of more than one element in fixed ratios.
• d. Chemical reactions involve atom rearrangement, not creation or destruction.
• e. Atoms are indestructible in chemical reactions.

3.

• a. J. J. Thomson
• b. Cathode - ray tube experiment
• c. Negative charge
• d. Outside the nucleus in the electron cloud
• e. Plum - pudding model

4.

• a. Ernest Rutherford
• b. Gold - foil experiment
• c. Positive charge
• d. In the nucleus
• e. Nuclear model

5.

• a. James Chadwick
• b. Experiment with beryllium radiation
• c. No charge (neutral)
• d. In the nucleus
• e. Refined Bohr - Rutherford model