2.1: The Atomic Theory of Matter2.2: The Discoexceptionally of Atomic Structure2.3: The Modern View of Atomic Structure2.4: Atomic Mass2.5: The Periodic Table2.6: Molecules and also Molecular Compounds2.8: Naming Inorganic Compounds2.9: Some Simple Organic Compounds

Why is it proper to reexisting the elepsychological form of helium as He yet imappropriate to represent the elemental develop of hydrogen as H?


Why is it proper to recurrent the elemental form of chlorine as Cl2 but imcorrect to reexisting the elemental form of calcium as Ca2?


Hydrogen exists as a diatomic molecule in its elemental form; helium does not exist as a diatomic molecule.

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Why is it proper to represent the elepsychological create of helium as He yet improper to recurrent the elemental develop of hydrogen as H?


Why is it correct to represent the elepsychological create of chlorine as Cl2 yet imappropriate to reexisting the elemental form of calcium as Ca2?


Conceptual Answers

The modern-day atomic concept states that all matter is composed of atoms. Atoms are the smallest parts of an facet that preserve the identification of that facet.

Numerical Problems

(Basic idea check) When 32.0 grams (g) of methane are shed in 128.0 g of oxygen, 88.0 g of carbon dioxide and 72.0 g of water are produced. Which legislation is this an example of? (a) Law of definite proparts (b) Law of conservation of mass or (c) Law of multiple proportions. (Law of Conservation of Mass) 8.00 grams (g) of methane are melted in 32.00 g of oxygen. The reactivity produces 22.00 g of carbon dioxide and an unmeasured mass of water. What mass of water is produced? (Law of Definite Proportions) Two experiments using sodium and also chlorine are perdeveloped. In the first experiment, 4.36 grams (g) sodium are reacted with 32.24 g of chlorine, making use of up all the sodium. 11.08 g of sodium chloride was produced in the first experiment. In the second experiment, 4.20 g of chlorine reacted via 20.00 g of sodium, using up all the chlorine. 6.92 g of of sodium chloride was created in the second experiment. Sjust how that these outcomes are continual via the legislation of constant complace. (Law of Conservation of Mass): 36.0 grams (g) of wood are melted in oxygen. The products of this reaction weigh 74.4 g. (a) What mass of oxygen is necessary in this reaction? (b) What mass of oxygen is needed to burn 8.00 lb of wood? 1 lb = 453.59237 g. (Law of Definite Proportions): A sample of methane contains only carbon and also hydrogen, through 3.00 grams (g) of carbon for eextremely 1.00 g of hydrogen. How a lot hydrogen must be present in a different, 50.0 g exact same of methane?

Numerical Solutions

The answer is (b) Law of conservation of mass. The number of grams of reactants (32.0 g of methane and also 128.0 g of oxygen = 160.0 g total) is equal to the number of grams of product (88.0 g of carbon dioxide and 72.0 g of water = 160.0 g total). The answer is 18.00 g of water. Due to the fact that the just products are water and carbon dioxide, their total mass need to equal the complete mass of the reactants, methane and also oxygen. 8.00 g of methane + 32.00 g of oxygen = 40.00 complete g of reactants. Because the total mass of the reactants amounts to the complete mass of the commodities, the total mass of the commodities is additionally 40.00 g. Thus, 40.00 complete g of products = 22.00 g carbon dioxide + unwell-known mass water. 40.00 full g of commodities - 22.00 g carbon dioxide = 18.00 g water.

To fix, determine the percent of sodium in each sample of sodium chloride. There is 4.36 g sodium for eexceptionally 11.08 g of sodium chloride in the initially experiment. The amount of sodium in the sodium chloride for the second experiment should be discovered. This is discovered by subtracted the recognized amount of reacted chlorine (4.20 g) from the amount of sodium chloride (6.92 g). 6.92 g sodium chloride - 4.20 g chlorine = 2.72 g sodium.

Hence, the percent of sodium in each sample is represented below: % Na = (4.36 g Na)/(11.08 g NaCl) x 100% = 39.4% Na % Na = (2.72 g Na)/(6.92 g NaCl) x 100% = 39.3% The slight difference in compositions is as a result of considerable figures: each percent has an uncertainty of .01% in either direction. The two samples of sodium chloride have actually the same complace.

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The answer is 38.4 g of oxygen. The full mass of the commodities is 74.4 g. Therefore, the total mass of the reactants should equal 74.4 g as well. Therefore, 74.4 g products - 36.0 g lumber reactant = 38.4 g oxygen reactant. The answer is 8.53 lb of oxygen. From, (a) that it takes 38.4 g of oxygen to burn 18.0 g of hardwood. First, transform both of these values to pounds (alternatively, the 8.00 lb can be converted to grams).

Now 2 ratios equal to each other deserve to be erected to determine the unrecognized mass of oxygen.

The answer is 12.5 g of hydrogen. If tbelow are 3.00 g of carbon current for eextremely 1.00 g of hydrogen, we have the right to assume the smallest whole number combination of these elements in that ratio to be 4.00 g of methane: 50.0 g methane x (1.00 g hydrogen)/(4.00 g methane) = 12.5 g of hydrogen.


Describe the experiment that provided evidence that the proton is positively charged. What monitoring led Rutherford to propose the presence of the neutron? What is the distinction between Rutherford’s version of the atom and also the design steustatiushistory.orgists use today? If cathode rays are not deflected when they pass via a region of area, what does this indicate about the existence or absence of a magnetic field perpendicular to the path of the rays in that region? Describe the outcome that would certainly be meant from Rutherford’s experiment if the charge on α pshort articles had actually continued to be the same however the nucleus were negatively charged. If the nucleus were neutral, what would certainly have actually been the outcome? Describe the differences between an α pshort article, a β particle, and a γ ray. Which has actually the biggest capacity to permeate matter?

Numerical Problems

Please be sure you are familiar with the topics questioned in Section 1.6 prior to proceeding to the Numerical Problems.

Using the information in Table 1.3 and the regular table, calculate the percent of the mass of a silicon atom that is as a result of electrons. proloads. Using the data in Table 1.3 and also the routine table, calculate the percentage of the mass of a helium atom that is due to electrons. proloads.
The radius of an atom is about 104 times larger than the radius of its nucleus. If the radius of the nucleus were 1.0 cm, what would be the radius of the atom in centimeters? in miles? The complete charge on an oil drop was uncovered to be 3.84 × 10−18 coulombs. What is the full variety of electrons included in the drop?