C02 - Structure Of Atom

Carbon is an element because it is a pure substance that cannot be broken down into simpler substances by chemical means. It is composed of only one type of atom, which is carbon. Air is a mixture of different gases, Stim is not a known substance, and Napthalene is a compound made up of carbon and hydrogen atoms. Therefore, carbon is the only option that fits the definition of an element.

Diffusion is the process by which particles move from an area of high concentration to an area of low concentration. This process is a direct result of the kinetic theory of matter, which states that all particles are in constant motion. Diffusion occurs because the particles are constantly moving and colliding with each other, causing them to spread out and distribute evenly. Therefore, diffusion is a process that provides evidence for the kinetic theory of matter.

Based on the symbols in the diagram, we can see that the symbol for chlorine atom is Cl. Therefore, it is true that the symbol for chlorine atom is Cl.

The nucleus of an atom contains both protons and neutrons. Protons have a positive charge and are responsible for determining the atomic number of an element. Neutrons have no charge and help stabilize the nucleus by balancing the repulsive forces between protons. Electrons, on the other hand, are found outside the nucleus in electron shells and are negatively charged. Therefore, the correct answer is both protons and neutrons.

The correct symbol for atom X is B. The proton number of an atom represents the number of protons in its nucleus, which in this case is 9. The nucleon number, also known as the mass number, represents the total number of protons and neutrons in the nucleus, which in this case is 19. Therefore, the symbol for atom X should have 9 protons and 19 nucleons, which is represented by option B.

The diagram shows the process of boiling, which is the change of state from a liquid to a gas. This is evident from the upward arrows indicating the release of gas particles. Boiling occurs when a substance is heated to its boiling point, causing the liquid particles to gain enough energy to overcome the intermolecular forces and escape into the gas phase. Therefore, process X in the diagram is boiling.

The diagram shows the particles arranged in a random and dispersed manner. This indicates that the substance is in a gaseous state at room temperature. Among the given options, only Helium is a gas at room temperature, making it the correct answer.

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The diagram shows an apparatus set up to investigate Process X. Diffusion is the movement of particles from an area of high concentration to an area of low concentration. In the given diagram, there is a concentration gradient indicated by the arrows, suggesting the movement of particles from one side to the other. This is characteristic of diffusion, making it the correct answer.

Diagram D shows the arrangement of the helium atoms in an enclosed cylinder. The helium atoms are evenly distributed throughout the cylinder, with no specific pattern or arrangement. This is because helium atoms are small and have weak intermolecular forces, allowing them to move freely and occupy the entire space within the cylinder. Therefore, diagram D accurately represents the arrangement of helium atoms in an enclosed cylinder.

The process occurring in the experiment shown in Diagram 1 is diffusion. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. In this case, the purple color of the water indicates that a substance has been added to it, and over time, the particles of this substance spread out evenly throughout the water, resulting in the purple color diffusing throughout the entire solution.

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Substances K and L exist as liquids at room temperature because their boiling points are below room temperature. J has a higher boiling point, so it exists as a solid at room temperature. M and N have even higher boiling points, so they exist as gases at room temperature.

Ammonium chloride is the substance that sublimes when heated. Sublimation is the process in which a solid directly turns into a gas without passing through the liquid state. When heated, ammonium chloride undergoes sublimation, meaning it goes from a solid directly to a gas, without melting into a liquid first. This is due to the compound's unique chemical properties and its ability to vaporize at a relatively low temperature.

Process X is sublimation. Sublimation is the process in which a solid directly changes into a gas without going through the liquid state. In the given diagram, it shows particles arranged in a solid state on one side and in a gaseous state on the other side, indicating the direct transition from solid to gas, which is characteristic of sublimation.

When steam converts into ice, the molecules lose speed. This is because steam is in the gaseous state and the molecules are moving rapidly and freely. However, when steam cools down and condenses into ice, the molecules slow down and become tightly packed. Therefore, the conversion from steam to ice involves a decrease in molecular speed.

Iodine will sublimate when heated because it undergoes a phase change directly from a solid to a gas without passing through the liquid phase. Sublimation occurs when the vapor pressure of a solid exceeds atmospheric pressure at a given temperature, causing the solid to transform into a gas. In the case of iodine, heating it causes the solid iodine crystals to vaporize and form a purple-colored gas.

An atom of oxygen-18 has 8 electrons, which is the same as the number of protons in the nucleus. Since the atomic number of oxygen is 8, this means that oxygen-18 has 8 protons. The atomic mass of oxygen-18 is 18, so to find the number of neutrons, we subtract the number of protons from the atomic mass. Therefore, an atom of oxygen-18 contains 10 neutrons.

The first step in a scientific investigation is identifying the problem. Before any research or experimentation can take place, scientists must clearly define the problem they wish to solve or the question they want to answer. This step helps to focus the investigation and guide the subsequent steps of making observations, forming a hypothesis, and planning an experiment. Identifying the problem is crucial in ensuring that the scientific investigation is purposeful and targeted towards finding a solution or gaining new knowledge.

The correct answer is B because it shows the correct type of particle for each substance.

Ethanol contains molecules because it is an organic compound composed of carbon, hydrogen, and oxygen atoms. Molecules are formed when atoms bond together, and in the case of ethanol, the carbon, hydrogen, and oxygen atoms combine to form the molecule of ethanol. Zinc, sodium chloride, and magnesium oxide, on the other hand, do not contain molecules. Zinc is an element, and elements exist as individual atoms. Sodium chloride and magnesium oxide are both compounds, but they are formed by the attraction of ions, not molecules.

Magnesium oxide is an ionic compound because it is formed by the transfer of electrons between magnesium and oxygen atoms. Magnesium has a tendency to lose two electrons, becoming a positively charged ion (Mg2+), while oxygen has a tendency to gain two electrons, becoming a negatively charged ion (O2-). The resulting attraction between these oppositely charged ions forms the ionic bond in magnesium oxide. In contrast, ethanol, sulphur dioxide, and tetrachloromethane are covalent compounds, where electrons are shared between atoms rather than transferred.

The correct answer can be deduced from Diagram 6 because at the freezing point of a substance, the temperature remains constant as the substance changes from a liquid to a solid. In Diagram 6, there is a horizontal line at 70 degrees Celsius, indicating that Y is freezing and transitioning from a liquid to a solid at this temperature.

The correct answer is D because the symbols for the elements chromium, copper, manganese, and potassium are Cr, Cu, Mn, and K, respectively.

The statements about diffusion explain situations I and II because both involve the movement of tiny particles (bromine gas and aqueous copper(II) sulphate) in a random and discrete manner.

Argon is a chemical element with the symbol Ar and atomic number 18. It is a noble gas and exists as individual atoms. Nitrogen, chlorine, and ammonia are all compounds that consist of molecules made up of multiple atoms bonded together. However, Argon is the only substance listed that is made up of individual atoms.

The observation that the whole test tube of water becomes purple in color suggests that the particles in potassium manganate(VII) are moving randomly. This is because diffusion is the movement of particles from an area of high concentration to an area of low concentration, and the fact that the color has spread evenly throughout the water indicates that the particles are moving randomly and spreading out uniformly.

James Chadwick suggested the atomic model shown in Diagram 1.

The statement that "protons and neutrons are found in the nucleus of an atom" is true. Protons and neutrons are subatomic particles that are located in the nucleus of an atom, which is the central region of the atom. The nucleus contains most of the mass of the atom, and the protons have a positive charge while the neutrons have no charge. This statement accurately describes the location and nature of these subatomic particles within an atom.

The diagram shows the arrangement of particles in a substance at room temperature. Oxygen is the correct answer because the diagram represents the arrangement of particles in oxygen at room temperature.

The observation in the experiment can be explained by the fact that the particles in copper(II) sulphate are minute and discrete. This means that the particles are very small and separate from each other. As a result, when the copper(II) sulphate is added to the agar, the particles can easily mix and dissolve in the agar. The small size and discrete nature of the particles allow for efficient mixing and dissolution.

Based on the given information, substance P is a solid at its melting point.

Niels Bohr introduced the model of the atom shown in the diagram. His model, known as the Bohr model, proposed that electrons orbit the nucleus in specific energy levels or shells. This model was a significant advancement in understanding atomic structure and helped explain the stability of atoms.

Ernest Rutherford is the correct answer because he made significant contributions to the understanding of atomic structure. He discovered the existence of the proton, which is a subatomic particle found in the nucleus of an atom. Rutherford also proposed the nuclear model of the atom, which states that most of the mass of an atom is concentrated in the nucleus. He conducted the famous gold foil experiment, which led to the discovery that the electrons move in empty space around the nucleus.

Elements V and Y have the same number of valence electrons. This is because valence electrons are the electrons in the outermost energy level of an atom, and they determine the chemical properties of an element. Looking at Table 3, we can see that V has 5 valence electrons and Y also has 5 valence electrons. Therefore, V and Y have the same number of valence electrons.

When steam converts into ice, energy is released. This is because the process of condensation occurs, where the steam loses heat energy and transforms into a solid state. This release of energy is due to the change in the molecular arrangement and the formation of stronger intermolecular forces in the ice.

Based on the information given, substance M has a melting point and boiling point that are not specified. However, it is stated that the physical state of substance M at room temperature is gas. This suggests that substance M has a low melting point and boiling point, causing it to exist as a gas at room temperature.

The correct answer is III and IV only. This is because in Figure 11, substance III shows a regular and orderly arrangement of particles, which is characteristic of a crystalline solid. Substance IV, on the other hand, shows a random and disordered arrangement of particles, which is characteristic of a gas. Therefore, these pairs are correctly matched.

The electron arrangement for an atom of element T is 2.8.2. This means that the atom has 2 electrons in the first energy level, 8 electrons in the second energy level, and 2 electrons in the third energy level. This arrangement is consistent with the element having the same chemical property as the element with the proton number of 20.

Based on the given graph, the temperature of substance X is increasing over time. This indicates that the substance is being heated. At the sixth minute, the temperature is still rising, suggesting that the heating process is ongoing. Therefore, it can be inferred that some molecules of substance X are closely packed together, while others are moving freely. This is because the increasing temperature causes the molecules to gain kinetic energy and move more rapidly, but not all molecules have reached the same level of energy distribution, resulting in some being closely packed while others move freely.

Ammonium chloride changes to the gaseous state when it is heated. This is because ammonium chloride is a compound that undergoes sublimation, which means it directly converts from a solid to a gas without passing through a liquid state. When heated, the strong ionic bonds between the ammonium (NH4+) and chloride (Cl-) ions break, and the compound vaporizes into ammonia gas (NH3) and hydrogen chloride gas (HCl). This process is endothermic, meaning it requires energy input to occur.

The correct answer is "The nucleus of the atom contains proton." This statement is true because Ernest Rutherford's atomic model proposed that the atom consists of a small, dense, positively charged nucleus at the center, which contains protons. The electrons, on the other hand, move in shells or orbits around the nucleus. This model is known as the Rutherford model or the planetary model of the atom.

Based on the information provided in the table, substance Z is a liquid at a certain temperature. This can be inferred because the table shows the melting point and boiling point of the substances, and Z is the only substance that has a boiling point but no melting point listed. This indicates that Z exists as a liquid at temperatures above its boiling point.

The electron configuration of an atom represents the arrangement of electrons in its energy levels. In the periodic table, elements in the same group have similar electron configurations. Since Y is below Z in the same group, it means that Y has one more energy level than Z. The proton number of Z is 12, which corresponds to the element magnesium (Mg). The electron configuration of Mg is 2.8.2. Therefore, the electron configuration for atom Y, which has one more energy level, would be 2.8.8.2.

The atomic model shown in Diagram 3 proposes that electrons move in shells around the nucleus. This idea was proposed by Neil Bohr, making statement I true. Statement II is false because the existence of the neutron was not the basis for this atomic model. Statement III is true because the diagram clearly shows the electrons arranged in different shells around the nucleus. Statement IV is false because the atomic model was not discovered through the bombardment experiment of alpha particles on gold foil. Therefore, the correct answer is I and III only.

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J.J. Thompson introduced the model of an atom.

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Sulphide and chlorine ions have the same number of electrons because the number of electrons in an ion is determined by the number of protons in the nucleus. Since both sulphide and chlorine ions have different numbers of protons (S=16, Cl=17), they will have a different number of electrons to balance out the charge and achieve stability. Therefore, the statement that they have the same number of electrons is incorrect.