The Lewis atomic model proposed that electrons are arranged around the nucleus in specific energy levels, which was further detailed by Niels Bohr to include allowed circular orbits. Bohr's model introduced the concept that these orbits, or energy levels, are quantized and designated with the quantum number 'n'. Lewis diagrams also show valence electrons around an atom's symbol, helping to visualize bonding.
Explanation:The Lewis atomic model suggests that electrons are arranged around the nucleus in specific energy levels, represented as rings or shells. This model of atomic structure was expanded upon by Niels Bohr in 1913. Bohr's model for the hydrogen atom incorporated quantum concepts and classical mechanics to propose that electrons move in fixed orbits, or quantized energy levels, around the nucleus. Each orbit represents a different energy level and is denoted by the principal quantum number 'n'. Bohr's model of the atom was a significant step forward from previous models, like the cubic model and the Saturnian model, and it introduced the idea that electrons could only exist in certain allowed energy states.
Notably, in Bohr's model, an electron in a hydrogen atom moves around the nucleus in circular orbits centered at the nucleus. The orbits are allowed to have only certain radii, which are in specific energy levels or shells designated by a number and the symbol 'n'. This concept also applies to more complex atoms, where electrons occupy regions of space, known as orbitals, around the nucleus based on their energy levels. This model was pivotal in explaining phenomena such as the discrete emission spectra of hydrogen.
Lewis diagrams, also known as Lewis electron dot diagrams, are a representation that shows the valence electrons as dots around the chemical symbol of an atom, thus giving us a visual representation of the valence electron arrangement in atoms and aiding in the understanding of chemical bonding and molecule formation.
Parts of Dalton’s atomic theory were disproved. Do you think that this should be taken as a criticism of Dalton as a scientist? Use a description of what you think a good scientist is to support your answer
In which group do all atoms have seven valence electrons in the ground state?
Group 7A or the 17th column on the periodic table, known as the halogens, contains elements with seven valence electrons. Their electron configuration is ns²np5.
The group in which all atoms have seven valence electrons in the ground state is the halogen group, also known as Group 7A or the 17th column of the periodic table. These elements have the valence shell electron configuration of ns²np5, where n represents the principal quantum number corresponding to the period number of the element in the periodic table. For example, chlorine (Cl) has the electron configuration [Ne] 3s² 3p5, indicating that it has seven valence electrons. This is because the p subshell is being filled with five electrons alongside the two electrons in the s subshell, summing up to seven valence electrons.
How many grams of sodium iodide, nai, must be used to produce 97.1 g of iodine, i2?
The process of removing an electron from a stable nucleus is known as
Which of the following depends on an object's displacement not distance from the starting point?
Question 2 options:
Velocity
Acceleration
Displacement
Speed
Answer: The velocity of an object depends on an object's displacement.
Explanation:
Velocity is defined as displacement of an object with respect to time.
It is a vector quantity measured in meter per second or m/s.
Mathematically
[tex]v=\frac{displacement}{\text{time taken}}[/tex] or [tex]v=\frac{dx}{dt}[/tex]
according to Le chateliers principle when a change is introduced into a system in chemical equilibrium the equilibrium shifts.
A) to the forward reaction.
B) to the reverse reaction
C) In the direction that relieves the change
D) in the direction that requires the most energy
why didn't mendeleev include helium , neon and argon in his periodic table?
Answer choices are:
A. These elements did not fit in with his pattern.
B. These elements are gases and he didn't include gases.
C. The atoms of these elements had no atomic mass.
D. These elements had not yet been discovered.
___________________________________________________________
Correct answer choice is:
D. These elements had not yet been discovered.
____________________________________________________________
Explanation:
Mendeleev would have no precise logic to presume there were lacking elements when they can be distributed by various units. But he did note bearings and was capable to divine some holes based on these bearings. The whole column of noble gases, though, could be dropped as it was a periodic recess, not a recess in the period.
Mendeleev added the noble gases later, near the edge of his life, during enough proof was received.
How many moles of water are produced when 3.45 moles of KMnO4 react? Give your answer to the nearest 0.1 moles
Final answer:
The number of moles of water produced when 3.45 moles of KMnO₄react is 5.2 moles.
Explanation:
To determine the number of moles of water produced when 3.45 moles of KMnO₄ react, we need to look at the balanced chemical equation for the reaction. Let's assume the reaction is balanced as follows:
2 KMnO₄ + 3 H₂O -> 2 MnO₂+ 2 KOH + 3 O₂
From the balanced equation, we can see that 3 moles of water are produced for every 2 moles of KMnO₄ reacted. Therefore, if 3.45 moles of KMnO4 react, we can calculate the number of moles of water produced using a proportion:
(3.45 moles KMnO₄) x (3 moles H₂O / 2 moles KMnO₄) = 5.175 moles H₂O
Rounding it to the nearest 0.1 moles, the number of moles of water produced is 5.2 moles.
When 3.45 moles of KMnO4 react, approximately 6.9 moles of water are produced. Rounding to the nearest 0.1 mole, the answer is 6.9 mol.
To find the moles of water produced, we need to follow these steps:
1. **Balance the chemical equation:** The balanced equation for the reaction of KMnO4 with water is:
2KMnO4 + 8H+ -> 2Mn2+ + K2SO4 + 4H2O
2. **Use the stoichiometric coefficients:** From the balanced equation, we see that for every 2 moles of KMnO4 that react, 4 moles of water are produced.
3. **Calculate the moles of water:**
- Moles of water produced = (Moles of KMnO4 reacted) * (Moles of water produced per mole of KMnO4)
- Moles of water produced = (3.45 mol) * (4 mol H2O / 2 mol KMnO4)
- Moles of water produced = 6.9 mol
Therefore, when 3.45 moles of KMnO4 react, approximately 6.9 moles of water are produced. Rounding to the nearest 0.1 mole, the answer is 6.9 mol.
Which of the following is not true of a pseudoscience? (1 point) It does not follow the scientific method. It is not proven reliable through experimentation. It is a practice or belief that claims to be science. It is a science that is controversial or unproven.
Answer: It is a science that is controversial or unproven.
Explanation:
Pseudoscience can be based upon the belief, statements or practices that are claimed to be factual as well as scientific but actually not. As it is not proved by the scientific experimental procedures. Hence, it cannot be considered as scientific but can become controversial and unproven as it lack evidences.
How to determine is an alcohol has strong or weak intermolecular forces?
Which compounds are used in mineral-based sunscreens?
The correct answer is A. The compounds used in mineral-based sunscreens are zinc oxide (ZnO) and titanium dioxide (TiO₂).
The compounds used in mineral-based sunscreens are Zinc oxide (ZnO) and Titanium dioxide (TiO₂). Zinc oxide and titanium dioxide are effective at protecting from the sun. These compounds effectively protect the skin by reflecting, scattering, and absorbing UV radiation.
They work by sitting on top of the skin and reflecting, scattering, and absorbing ultraviolet (UV) radiation rather than allowing it to penetrate the skin.
Complete Question:
Which compounds are used in mineral-based sunscreens?
a. ZnO and TiO₂
b. ZnO and CdS
c. TiO₂ and SiO₂
d. CdS and SiO₂
Barium ions carry a 2+ charge, and nitrogen ions carry a 3-charge. what would be the chemical formula for the ionic compound barium nitride?
What three elements are present in monosaccharides?
How many moles of oxygen are in 5.6 moles of al(oh)3?
Which of the following units is not a fundamental unit?
A) Gram
B) Kilogram
C) Meter
D) Second
The one that is not a fundamental unit is gram. The correct option is A.
What are fundamental units?The basic units are those defined by the International System of Units. Because these units are not derived from any other unit, they are referred to as fundamental units.
The seven fundamental units are as follows: meter (m) for length. Time is measured in seconds (s).
A base unit is a unit of measurement used to measure a fundamental quantity.
A base quantity is one of a conventionally chosen subset of physical quantities in which none of the quantities can be expressed in terms of the others.
The fundamental units of electric current, length, and temperature are ampere (A), meter (m), and Kelvin (K), respectively.
The kilogram (kg) is the fundamental unit of measurement for mass. The gram (gm) is not a fundamental unit of measurement.
Thus, the correct option is A.
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Toy balloons are filled with hydrogen gas, at standard temperature, from a 10.0-liter cylinder. the initial pressure of the gas in the cylinder is exactly 100 atm. assuming each balloon is filled to a volume of 1.0 liter at standard pressure, how many balloons could be filled?
Chanice drives her scooter 7 kilometers north she stops for lunch and then drives 5 kilometers east what distance did she cover?? What was her displacement
Answer:
Total distance of covered by Chanice is 12 km
8.60 km was her displacement in the direction of north-east.
Explanation:
Distance covered by Chanice in north direction = 7 km
Distance covered by Chanice in an east direction = 5 km
Total distance of covered by Chanice = 7 km+ 5 km = 12 km
Displacement is defined as shortest distance from initial point to final point.
In a ΔABC, the displacement of the Chanice = AC
ΔABC, is a right angled triangle.So, by applying Pythagoras theorem we can determine the the length of AC.
[tex]AB^2+BC^2=AC^2[/tex]
[tex](7 km)^2+(5 km)^2=AC^2[/tex]
AC = 8.60 km
8.60 km was her displacement in the direction of north-east.
Final answer:
The distance Chanice covered on her scooter is the sum of her northward and eastward travels, 12 km. Her displacement is the hypotenuse of the right triangle formed by her path, approximately 8.6 km. The magnitude of her displacement is also about 8.6 km.
Explanation:
Chanice drives her scooter 7 kilometers north and then 5 kilometers east. The distance she covered is the total length of her travel path, which is the sum of these two separate distances.
The displacement, however, is the shortest path between her starting and ending points, measured in a straight line. In Chanice's case, we can calculate this by envisioning a right triangle where the legs of the triangle are her northward and eastward paths. The hypotenuse of this triangle will be her displacement. Using the Pythagorean theorem, displacement (Δd) can be calculated as Δd = √(7² + 5²) = √(49 + 25) = √74, which is approximately 8.6 kilometers.
The magnitude of her displacement is the absolute value of her displacement, which is simply the hypotenuse calculated above, about 8.6 kilometers.
AB + C → AC + B is the general equation for which one of the following types of chemical reactions?
What is the range of the numbers of isotopes chemical elements have?
The range of the number of isotopes that chemical elements can have is b
. 3 to 36.
The element with the least (3) number of isotopes is Hydrogen, while the elements with the most number (36) of possible isotopes are Xenon and Cesium.
Isotopes are different forms of the same element, in which the number of protons in the nucleus of the atom is the same for the different forms, but the number of neutrons in the nucleus is different. Isotopes are atoms with the same number of protons but different numbers of neutrons. The range of isotopes for chemical elements varies, with some elements having multiple isotopes. Isotope stability can vary among different isotopes of an element.Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons, leading to different mass numbers. The range of isotopes for chemical elements can vary significantly. For instance, thallium has 25 isotopes with atomic masses ranging from 184 to 210.The stability of isotopes differs, with some being more stable than others.
Correct question is: What is the range of the numbers of isotopes chemical elements have?
a. 4 to 45
b. 3 to 36
c. 2 to 34
d. 5 to 12
What is material that will sink in Liquid water @ 4c
A. Aluminum
B. Corn oil
C. Ice
D gasoline
When calcium (ca) bonds with oxygen, it gives up two electrons. what is the charge of the ca ion in this compound?
Explanation:
Atomic number of calcium is 20 and its electronic distribution is 2, 8, 8, 2. Hence, to attain stability it will readily lose its valence electrons.
Hence, neutral Ca atom will change into [tex]Ca^{2+}[/tex] ion.
Whereas atomic number of oxygen is 8 and its electronic distribution is 2, 6. Hence, to attain stability it will needs to gain two electrons.
Hence, neutral O atom will change into [tex]O^{2-}[/tex] ion.
Therefore, when both calcium and oxygen atoms will chemically combine with each other then according to cross multiplication same charges will be cancelled out resulting in the formation of calcium oxide (CaO) compound.
Thus, we can conclude that charge on calcium in this compound is +2.
For which atom is it difficult to predict the most probable ionic charge using the periodic table?
The atom for which the prediction of ionic charge has been difficult based on the periodic table is Cobalt.
The ionic charge has been imposed on the atom when there has been a loss or gain of an electron, in order to achieve the stable electronic configuration. The elements on the loss of electron have attained a +ve charge, while the gain of an electron by an atom gives it a -ve charge.
The elements in the periodic table have an oxidation state for the ionic form of the elements. The varying oxidation state element has been able to attain a varying ionic state. Cobalt has been present with varying oxidation states, thus it has been difficult to predict the ionic charge of Cobalt using the periodic table.
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Identify the subshell corresponding to the lowest energy peak in the photoelectron spectrum (pes) of sulfur.
More than two-thirds of the elements of the periodic table are classified as
Answer:
More than two-thirds of the elements of the periodic table are classified as Metals
Explanation:
Metals are the most abundant elements of the Periodic Table and of the earth's crust: of the 118 known, 25 are non-metallic.
Metals are characterized by being good thermal and electrical conductors and having high densities. They are generally solid at room temperature (with the exception of mercury). In addition, almost all reflect the light, obtaining a very characteristic brightness.
As mentioned, metals have among their main characteristics the possibility of being good conductors of electricity because they oppose low resistance, therefore, the electric charge can easily pass through these elements. They are also excellent heat conductors because they oppose poor resistance to high temperatures.
The metals have the malleability property, this allows their forms to be modified through the application of a continuous pressure force or after a casting process.
They also have ductility as their characteristic property, this is the possibility of molding metals into thin wires or resistant wires.
Metals are also characterized by their high tenacity, that is, by being highly resistant throughout the deformation processes before they break. The tenacity of metals is due to the strong union of their molecules.
Metal elements are classified into different types:
Alkali metals. Alkaline earth metals. Transition metals: Most metals are transitional. Lanthanides: Called lantanoids or "Rare earths", they form the "elements of internal transition" next to actinides. Actinides: Metals of high atomic numbers. Transactinides: These are "super heavy" metals, which outnumber the heaviest of actinides: lawrencio (103).What does ph measure? the concentration of oxygen atoms in solution the total number of acid molecules in solution the concentration of hydrogen ions in solution the total number of base molecules in solution brainly?
Answer:
the concentration of hydrogen ions in solution
Explanation:
pH stands for potenz of hydrogen.
pH is measure of hydrogen ion concentration.
pH is calculated as :
pH = -log[H⁺]
where [H⁺] is concentration of hydrogen ions.
Thus pH is measure of hydrogen ions concentration.
the other statements are wrong
i) total concentration of oxygen is not related to pH measure.
ii) total number of acid molecules is also not direct measure of pH.
iii) total number of base molecules cannot be measure of pH.
Calculate the standard entropy change for the dimerization of no2: 2 no2(g) → n2o4(g) at 298 k, if s ◦ ∆h◦ f j k·mol kj mol no2(g) 240.06 33.18 n2o4(g) 304.29 9.16 answer in units of j k · mol
The standard entropy change for the dimerization of NO2 at a temperature of 298 K is calculated to be -175.83 J/K·mol.
Explanation:The probability of Type I error is denoted by alpha (α), and in hypothesis testing, we typically set a predetermined level of significance (α), which is the maximum allowable probability of making a Type I error.This incorrect rejection is often influenced by the level of significance used in the test. The likelihood of a Type I error occurring is often denoted by the Greek letter alpha, α. The lower the value of α, the less likely you are to make a Type I error.The standard entropy change for the dimerization of NO2 can be calculated using the equation: ΔS° = ΣS°(products) - ΣS°(reactants). The standard entropy (ΔS°) values for the reactants and products are given as follows: for NO2(g), S° = 240.06 J/K·mol; and for N2O4(g), S° = 304.29 J/K·mol. Therefore, the standard entropy change for the dimerization of NO2 at 298 K becomes:ΔS° = [1 x S°(N2O4)] - [2 x S°(NO2)] = [1 x 304.29 J/K·mol] - [2 x 240.06 J/K·mol] = -175.83 J/K·mol. The probability of Type I error is denoted by alpha (α), and in hypothesis testing, we typically set a predetermined level of significance (α), which is the maximum allowable probability of making a Type I error.This incorrect rejection is often influenced by the level of significance used in the test. The likelihood of a Type I error occurring is often denoted by the Greek letter alpha, α. The lower the value of α, the less likely you are to make a Type I error.
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_____ is a mixture of dead organic material that can be used as fertilizer
The answer is compost. It is an organic matter that has been disintegrated and cast-off as fertilizer and soil alteration. This is a significant component in organic farming. The procedure of composting necessitates creating a mound of wet organic substance identified as green wastes – these are leaves, food waste and waiting for the resources to collapse into humus after weeks or months.
What intermolecular forces occur between two methane molecules?
What is the name of the compound cs (mno4)2
a. Cadmium manganate
B. Cadmium manganate
C. Cadmium manganate
D. Cadmium permangantie
The name of the compound Cs(MnO4)2 is Cesium Permanganate.
Explanation:The compound Cs(MnO4)2 is correctly named as Cesium Permanganate. In this compound, Cs represents the element Cesium and MnO4 represents the polyatomic ion called Permanganate. The suffix -ate typically denotes ions that include oxygen
The compound Cs(MnO4)2 is called cesium permanganate.
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How can you determine if elements have similar chemical properties?
The similarity of chemical properties in elements can be determined by their position in the periodic table, specifically in the same group or period.
Similar chemical properties in elements can be determined by looking at their position in the periodic table and their electronic configurations.
Elements in the same group or column of the periodic table have similar chemical properties because they have the same number of valence electrons, which are responsible for bonding and chemical reactions. For example, all elements in Group 1 (alkali metals) have similar properties, such as being highly reactive and easily forming positive ions.
Additionally, elements in the same period or row of the periodic table have similar chemical properties because they have the same number of electron shells. For example, elements in Period 3 all have three electron shells, which influences their reactivity and bonding behavior.
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