1.
Who pictured the atom as a tiny sphere composed of a positivie jelly-like materak which accounts for the mass of an atom and had negatively charged electrons distributed throughout to "neutralize" the atom?
Correct Answer
C. Thomson
Explanation
Thomson is the correct answer because he proposed the plum pudding model of the atom, which described the atom as a tiny sphere composed of a positive jelly-like material. This positive material accounted for the mass of the atom, while the negatively charged electrons were distributed throughout to "neutralize" the atom. This model was later disproven by Rutherford's gold foil experiment, which led to the development of the nuclear model of the atom.
2.
Given credit with naming the "neutron"
Correct Answer
D. Chadwick
Explanation
Chadwick is credited with naming the "neutron". This is because James Chadwick, a British physicist, discovered the neutron in 1932 while working at the University of Cambridge. He conducted experiments that led to the identification of this subatomic particle, which had previously been unknown. Chadwick named it the neutron due to its neutral charge, as it lacks both a positive and negative charge. His discovery and naming of the neutron were significant contributions to the field of atomic physics.
3.
Plum Pudding Model of the Atom
Correct Answer
A. Thomson
Explanation
The correct answer is Thomson because he proposed the Plum Pudding Model of the Atom. This model suggested that an atom is made up of a positively charged sphere with negatively charged electrons embedded in it, resembling the distribution of plums in a plum pudding. Thomson's model was significant in understanding the structure of atoms and laid the foundation for further advancements in atomic theory.
4.
Suggested that equal volumes of gases at the same temperature and pressure have the smae number of molecules.
Correct Answer
C. Avogadro
Explanation
Avogadro's law states that equal volumes of gases at the same temperature and pressure contain the same number of molecules. This means that regardless of the type of gas, if the volume, temperature, and pressure are the same, the number of molecules will also be the same. This law is based on Avogadro's hypothesis, which states that equal volumes of gases at the same temperature and pressure contain an equal number of particles. Therefore, Avogadro is the correct answer for this question.
5.
Given credit for the first periodic table. Arranged his periodic table based on atomic weight and chemical reactivity.
Correct Answer
B. Mendeleev
Explanation
Mendeleev is given credit for the first periodic table because he arranged it based on both atomic weight and chemical reactivity. This means that he organized the elements in a way that showed their similarities and patterns in both their atomic weights and how they reacted chemically. This organization system was a major breakthrough in understanding the properties and relationships of the elements, and laid the foundation for the modern periodic table.
6.
Gold Foil Experiment
Correct Answer
A. Rutherford
Explanation
The correct answer is Rutherford because the Gold Foil Experiment was conducted by Ernest Rutherford in 1911. In this experiment, Rutherford bombarded a thin sheet of gold foil with alpha particles and observed their scattering patterns. The unexpected results of the experiment led to the discovery of the atomic nucleus and the proposal of the planetary model of the atom, with a small, dense, positively charged nucleus at the center. Rutherford's experiment played a crucial role in our understanding of the structure of the atom.
7.
Supported the Four Element Concept devised by Empedocles
Correct Answer
D. Aristotle
Explanation
Aristotle is the correct answer because he supported the Four Element Concept devised by Empedocles. This concept proposed that all matter is made up of four elements - earth, air, fire, and water. Aristotle further developed this concept by adding a fifth element, called aether, which he believed made up the celestial bodies. His ideas on the four elements and their properties had a significant influence on the development of scientific thought in ancient Greece.
8.
Believed the atom to be an indestructible, indivisible entity. Came up with the name "atom"
Correct Answer
A. Democritus
Explanation
Democritus believed that the atom is an indestructible and indivisible entity. He came up with the name "atom" to describe these fundamental particles. This concept of the atom being the smallest indivisible unit of matter was a significant contribution to the development of atomic theory. Democritus' ideas laid the foundation for later scientists to further explore and understand the nature of atoms and their behavior.
9.
Given credit for "Atomic Theory"
Correct Answer
D. Dalton
Explanation
Dalton is credited with the development of the Atomic Theory. This theory proposed that all matter is made up of tiny indivisible particles called atoms, which combine in specific ratios to form compounds. Dalton's theory also suggested that atoms of different elements have different properties and that chemical reactions involve the rearrangement of atoms. His work laid the foundation for modern atomic theory and greatly contributed to our understanding of the composition and behavior of matter.
10.
Given credit for the "electron"
Correct Answer
A. Thomson
Explanation
Thomson is given credit for the discovery of the electron. In his famous experiment, known as the cathode ray tube experiment, Thomson observed that a beam of particles, called cathode rays, were attracted to a positively charged plate, indicating the presence of negatively charged particles. He proposed that these particles were much smaller than atoms and carried a negative charge, which he called electrons. This discovery revolutionized the understanding of atomic structure and laid the foundation for the development of the modern model of the atom.
11.
Calculated that the atom consisted mostly of empty space through which electrons move and also concluded that there was a tiny, dense region "the nucleus" centrally located within the atom that contained all of an atom's positive charge and virtually all of its mass.
Correct Answer
D. Rutherford
Explanation
Rutherford calculated that the atom consisted mostly of empty space through which electrons move. He also concluded that there was a tiny, dense region called "the nucleus" centrally located within the atom. This nucleus contained all of an atom's positive charge and virtually all of its mass.
12.
Suggested that electrons can only be in discrete orbits, and that they absorb or emit energy in discrete amounts as they move from one orbit to another.
Correct Answer
C. Bohr
Explanation
Bohr's model of the atom proposed that electrons can only exist in specific energy levels or orbits around the nucleus. This was a departure from Thomson and Rutherford's models, which did not account for the quantized nature of electron energy. Bohr's model also explained that when electrons transition between these energy levels, they either absorb or emit energy in discrete amounts, known as quanta. This concept of discrete energy transitions provided a better explanation for the observed line spectra of elements, supporting Bohr's model. Heisenberg's uncertainty principle, on the other hand, deals with the limitations in simultaneously measuring the position and momentum of a particle, and is unrelated to the quantization of electron energy levels.
13.
Uncertainty Principle
Correct Answer
A. Heisenberg
Explanation
The Uncertainty Principle, also known as Heisenberg's Uncertainty Principle, is a fundamental principle in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position and momentum, can be known simultaneously. This principle was formulated by Werner Heisenberg in 1927 and has had a profound impact on our understanding of the microscopic world. Therefore, the correct answer to the question is Heisenberg.
14.
Planetary Model of the Atom
Correct Answer
B. Bohr
Explanation
The correct answer is Bohr. The question is asking for the scientist associated with the Planetary Model of the Atom. The Planetary Model of the Atom was proposed by Niels Bohr in 1913. In this model, Bohr suggested that electrons orbit the nucleus in specific energy levels or shells, much like planets orbiting the sun. This model helped explain the stability of atoms and the emission and absorption of light.
15.
Given credit with discovery of the proton.
Correct Answer
B. Rutherford
Explanation
Rutherford is credited with the discovery of the proton. In his famous gold foil experiment, Rutherford bombarded a thin sheet of gold with alpha particles and observed their deflection. He concluded that the atom has a tiny, dense, positively charged nucleus at its center, which he named the proton. This discovery revolutionized our understanding of atomic structure and laid the foundation for modern atomic theory.
16.
Stated "It is inherently impossible to know simultaneously both the exact momentum of the electron and its exact location in space."
Correct Answer
D. Heisenberg
Explanation
Heisenberg's uncertainty principle states that it is impossible to simultaneously know both the exact momentum and the exact position of a particle, such as an electron. This means that the more precisely we try to measure one of these properties, the less precisely we can know the other. This principle is a fundamental concept in quantum mechanics and has profound implications for our understanding of the behavior of particles at the microscopic level.
17.
Discovered that the trend that placed elements in their order on the periodic table was the number of protons. Given credit for the modern periodic table.
Correct Answer
B. Moseley
Explanation
Moseley is the correct answer because he discovered that the trend that placed elements in their order on the periodic table was based on the number of protons. This discovery was crucial for the development of the modern periodic table. Mendeleev is also credited with the creation of the periodic table, but Moseley's contribution specifically regarding the number of protons is what sets him apart in this context. Rutherford and Einstein made significant contributions to the field of physics, but their work did not directly relate to the organization of elements on the periodic table.