CHEMISTRY

CHEMISTRY



CHEMISTRY

Did Democritus use the scientific method to study the existence of atoms?

Ans)Democritus' (460BC-370BC) idea about the existence of atoms was based on reasoning rather than science, and drew on the findings and teachings of two Greek philosophers. Considering the resources and tools, it was almost impossible to deduce the existence of atoms through an experiment. However, his undeniably witty observation laid the foundation of modern science.

2.Did Dalton use the scientific method in his studies of the existence of atoms?

Ans)Dalton's atomic theory was somewhat based on scientific method as he deduced the atom structure based on series of observations on weather. He found that water droplets were found in air and the amount of water varied. Moreover, it has been proposed that his theory was deduced from the researches on ethylene and methane, or by analyzing nitrous oxide.



3.Review six kinds of observational evidence that were used to support the atomic theory.

Ans)The Greek had already proposed that elements were composed of atoms and that atoms of same element were identical but different from the atoms of other elements. The second important observation was of Dalton who determined the atomic weights of many elements. Thomson was the person who added the third observation to the modern atomic theory by discovering the “electrons” with the use of cathode rays. Soon a fourth observation was brought to the world when “protons” were discovered in an experiment in which Rutherford bombarded alpha particles onto a gold foil. Rutherford laid the basis of the nuclear model of atom that is still accepted today. Later another observation by Niels Bohr led to the theory of “Quantum Mechanics” when he suggested that electrons jump from higher to lower orbits emitting energy. The final observation, by James Chadwick, led to the discovery of the presence of “neutron”.

4.What three particles make up every atom? What are the major differences among these particles?

Ans)The three particles that make up an atom are protons, neutrons and electrons. Protons, the positively charged particles, and neutrons are found in the nucleus of the atom. While electron, negatively charged particles, revolve around the nucleus in orbits. Neutrons, on the other hand, are neutral and carry no charge.

5.What is the largest part of the atom? Of what does it consist? Why are electrons and protons found in different parts of the atom?

Ans)The largest part of an atom is the nucleus, which consists of protons and neutrons. The electrons are found revolving around the nucleus in orbits. Electrons and protons are found in different parts of the atom to prevent them from clumping together due to attraction because they carry opposite charges.

6.Why is the smallest unit of an element an atom, but the smallest unit of a compound is a molecule?

Ans)Atom, derived from the Greek word “atomos” meaning indivisible, is considered the smallest part of an element because it is the smallest particle that can represent all the properties of the element. A molecule, formed when two or more elements chemically ...