4.Which scientist described the electrons as traveling in certain orbits or energy levels?

a.Dalton
b.Rutherford
c.Thomson
d.Bohr



5.In a famous experiment, scientists bombarded a very thin gold (Au) foil with positively charged alpha particles. They found that most of the alpha particles passed right through the Au foil. However, a few of the alpha particles were deflected or bounced back toward the source. How did these scientists explain their results?

a.Negative charges are spread throughout the atom.
b.Negative charges are located in the tiny nucleus of the atom.
c.Positive charges are located in the tiny nucleus of the atom.
d.Positive charges are spread throughout the atom.



6.The atomic mass represents the weighted average of an element’s

a.Ions
b.mass numbers
c.atomic numbers
d.isotopes



7.The number of protons is represented by the element’s

a.atomic number
b.mass number
c.atomic mass
d.isotope



8.The number of protons plus neutrons is represented by the

a.atomic number
b.mass number
c.atomic mass
d.isotope



9.How many valence electrons would an atom of Chlorine have?

a.2
b.3
c.7
d.8



10.An element is found to have 2 electrons in the 3rd energy level. What is this element?

a.Boron
b.Magnesium
c.Fluorine
d.Argon



11.Which shows the order of decreasing atomic size?

a.Si, Al, Mg, Na
b.I, Br, Cl, F
c.Be, Mg, Ca, Sr
d.C, P, Se, I



12.Which of the following elements has the highest ionization energy and why?

a.Argon because it has more protons in the nucleus.
b.Argon because it has a full valence shell.
c.Chlorine because it only needs one valence electron to fill its valence shell.
d.Chlorine because it attracts electrons better.



13.Which shows the order of increasing ionization energy?

a.Si, Al, Mg, Na
b.Ga, Ge, As, Se
c.Be, Mg, Ca, Sr
d.F, Cl, Br, I



14.Identify the reason why atoms decrease in size(atomic radius)across a period on the Periodic Table.

a.Gravity pulls the electrons in towards the nucleus.
b.Increase in energy levels increases the attraction and thus pulls electron cloud in.
c.Increasing strong positive nuclear charge from the nucleus pulls in the negative electron clouds and increases with the increase in protons and electrons.
d.Electrons lose energy and collapse with an increasing number of electrons and protons.



15.What is the shielding effect?

a.The neutrons shield protons from the attraction of the electrons from the first energy level.
b.Valence electrons are shared equally between atoms.
c.The repulsion of electrons in the same energy level.
d.The inner-core electrons shield outer-core electrons from the attraction to the atom’s nucleus.



16.Which statement is an accurate description of elements from Period 3 on the periodic table?

a.It contains elements with the same number of 3 protons.
b.It contains elements with the same number of3valence electrons.
c.It contains elements with the outermost protons in the same 3rd energy level.
d.It contains elements with the outermost electrons in the same 3rd energy level.



17.The column that an element is located in tells us

a.the total number of valence electrons an atom has.
b.the total number of energy levels an atom of that element has.
c.the highest energy level an atom of that element has.
d.both b & c.



18.The Halogen family of elements all have 7 valence electrons. Which column would they be in?

a.01 (IA)
b.02 (IIA)
c.4 (IVA) or 14
d.7 (VIIA) or 17



19.The Alkali and Alkaline Earth metals belong to which columns, respectively?

a.Column IA & IIA
b.Column VIIA & Column VIIIA
c.Column IIIA & IVA



20.What do carbon and silicon have in common?

a.They belong to the same column (family), therefore they have the same number of valence electrons.
b.They belong to the same column (family), therefore they have the same number of total electrons.
c.They belong to the same column (family), therefore they have the same number of energy levels.
d.They belong to the same column (family), therefore they have the same number of protons.



21.Electromagnetic radiation can take the form of which of the following types of waves

a.Heat
b.Light
c.Ultraviolet
d.All of the above



24.In order to go to a lower energy orbit, an electron

a.Must disappear
b.Must combine with other electrons
c.Lose energy of a specific amount
d.Must be transferred to another atom



25.Please choose the correct sequence that describes the excitement of an atom.
1. Such an electron transition raises the atom from the ground state to the excited state.
2. When energy is added to an atom from an outside source, its electrons move to a higher energy level (orbit)
3. As a result, the atom emits a photon.
4. When the atom is in an excited state, the electron can drop from the higher energy level to a lower energy level.

a.1, 2, 3, 4
b.4, 3, 2, 1
c.2, 1, 4, 3
d.3, 4, 1, 2

It contain 2 mol of HCl. To find the moles of HCl, you have to change the volume units into dm³ or liter.

How to calculate the value of that HCl mole?

As per data given:

Vacid = 100 cm³

Molacid = 0.2 mol/dm³ = 0.2 mol/L

First, we have to change volume unit into liter or dm³. So

Vacid =  100 cm³ = 0.1 L

Then calculate the moles of HCl:

Moles of HCl = Molacid : Vacid

Moles of HCl = 0.2 : 0.1

Moles of HCl = 0.2 x 10

Moles of HCl = 2 mol

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The mass of Be(NO₂)₂ required to make 550 mL of a 2.5 M solution is 126.25 g.

Molar concentration is a measurement of the concentration of a solute in a solution, in terms of the quantity of material per unit volume of solution. The number of moles per liter, represented by the unit sign mol/L or mol/dm³ in SI units, is the most common way to measure molarity in chemistry.

Mathematically;

Molar concentration = number of moles/volume in liters

The number of moles is also determined using the formula below:

Number of moles = mass/molar mass

Hence;

Molar concentration = mass / molar mass * volume in liters

Therefore:

mass = Molar concentration * molar mass * volume in liters

The molar mass of Be(NO₂)₂ = 101 g/mol

Mass of  Be(NO₂)₂ required = 2.5 * 500 * 1/1000 * 101

Mass of  Be(NO₂)₂ required = 126.25 g

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Atoms of different metals can differ in number of protons, electron configuration, atomic radius, melting/boiling point, hardness/ductility, and conductivity.

Atoms of different metals can differ from each other in a number of ways, including:

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The structure is attached with  the  answer. 5-tert-butyl-2-methyl-3-octyne is a hydrocarbon molecule with a chain of 14 carbon atoms, so it is an alkyne.

At the beginning of the chain is a triple bond, which is the characteristic feature of an alkyne. The chain also contains two methyl and one tert-butyl group. The methyl group is attached to the second carbon atom in the chain, while the tert-butyl group is attached to the fifth carbon atom in the chain.

This molecule has a total of 20 hydrogen atoms, with three hydrogen atoms attached to each of the carbon atoms in the chain.  5-tert-butyl-2-methyl-3-octyne is a relatively reactive molecule because of its triple bond. This molecule can undergo a variety of reactions, including addition reactions, oxidation reactions, and substitution reactions. The reactivity of this molecule makes it a useful chemical in a variety of industrial and laboratory applications.

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according to the question, All the reactions in a path are added together.

What is the reactions?

Reactions are the processes in which one or more substances are changed into one or more new substances. They are caused by a chemical change in which the atoms of the reactants rearrange to form the atoms of the products. Reactions can be classified according to the type of energy released or absorbed during the reaction, such as exothermic and endothermic. Reactions can also be classified according to the type of reactants involved, such as single-replacement and double-replacement reactions. Reactions can occur quickly and release a large amount of energy, or they can occur slowly and release little or no energy. Reactions can also occur in a series of steps, such as in a reaction mechanism. In general, reactions require reactants, a catalyst, and an energy source in order to occur.

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The ideal gas law describes the behavior of a gas under ideal conditions, which typically means that it is at a low density and a high temperature.

When these conditions are met, the gas will behave in a manner that is consistent with the ideal gas equation. Generally, a gas will exhibit its ideal properties when it is in a container with a large volume, has a low pressure, and is at a high temperature.

Additionally, the gas particles must be small and non-interacting, meaning that they do not interact with each other. When these factors are taken into account, a gas will most likely display the ideal gas properties predicted by the ideal gas law.

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An organism is considered extinct if the fossil evidence reveals the remains of one that is no longer present-day. As a result, scientists might conclude that the majority of Earth's animals are already extinct because they have noted that certain qualities and traits are absent from species that are still alive.

The phrase "extinction" refers to the end of a particular type of organism or a set of types, typically a species. Although the ability to reproduce and bounce back may have been lost earlier, the death of the last individual of the species is widely considered to be the moment of extinction.

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The amount of the aluminum oxide that is formed is  2.5 moles.

We must have it at the back of our minds that in the case of the questions that involves stoichiometry, the limiting reactant can be said to be the compound that is used up in the reaction.

We are told here that the substance that has been used up in this reaction is the aluminum then it means that this must be the limiting reactant here.

If 4 moles of aluminum produces 2 moles of aluminum oxide

5 moles of aluminum would produce 5 * 2/4

= 2.5 moles of aluminum oxide.

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You can compare the rates of effusion of two gases in a mixture by their molecular weights.

The square root of a gas's molecular weight has an inverse relationship with the rate of effusion of that gas. Therefore, you may compute the square roots of two gases' molecular weights and then invert that ratio to compare the rates of effusion of the two gases in a mixture.

The rate of effusion will be slower for the gas with the greater molecular weight and faster for the gas with the lower molecular weight.

For instance, the ratio of two gases' rates of effusion is given by R = (M1 / M2)-1 if their molecular weights are M1 and M2, respectively.

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Genetic modification of crops and food have both advantages and disadvantages. These techniques create desired characteristics in crops but latter that might affect our health as well.

Plants and animals can be genetically modified to create desired characteristics in them. Gene techniques such as CRISPER are nowadays becoming popular in agricultural field.

Features such as rapid growth, extra production, coloring, change in size, antibacterial properties, climate survival etc. can be imparted to plants by genetic engineering.

However, genetically modified crops make some health issues some times. It has been reported that, some genetically modified vegetables causes sever health impacts.

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Answer:

look at the attachment I wrote it out for you.

The parent component in the structure of 1,4- dimethyl cyclohexane is cyclohexane, which has two methyl groups attached at the first and fourth positions of the carbon ring.

Cyclohexane is a saturated hydrocarbon with the molecular formula CₙH₂ₙ where n represents the number of carbon atoms present in the organic compound. They are represented as simple polygons with the sides representing carbon-carbon bonds. Each carbon atom is held together by two hydrogen atoms. A molecule's multiple rings may share one or more common atoms. One carbon atom is shared by two rings in spirocyclic compounds. These compounds are uncommon.

According to the IUPAC system, cycloalkanes are named with the prefix cyclo-.

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Answer:Gas is the answer

The molar mass of the gas would be 16.36 g/mole.

The formula for molar mass: M = (m.RT)/ (P.V)

P stands for the pressure of the ideal gas

V stands for the volume of the ideal gas

R stands for the universal gas constant

T stands for the temperature.

In this case, we are given that:

P = 1 atm (standard conditions)

T = 273K (standard conditions)

R = 0.082 lit. atm. K⁻¹.mol⁻¹

Mass of gas (m) = 0.399 g

Volume of gas (V) = 550 mL = 0.55 L

Therefore, the molar mass of the gas would be:

M = (m.RT)/ (P.V)

M = (0.399 x 0.08206 x 273) / (1 x 0.55)

M = 16.36 g/mole

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a) The concentration of the hydrogen ions is  1 * 10^-7 M

b) The concentration of the hydroxide ions is  1 * 10^-7 M

c) Ratio of the hydrogen to the hydroxide ion is 1:1

We know that the pH of the solution would have to do with ratio of the hydrogen ion and the hydroxide ions that we have in the solution. We know that the pH values that range from 0 -6 is acid, 7 is neutral and 8 - 14 is basic.

Then we have that;

Concentration of the hydrogen ion in the solution is obtain from the formula;

[H^+] = Antilog (-pH)

At pH 7 we have;

[H^+] = Antilog (-7)

= 1 * 10^-7 M

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The answer is Two molecules of carbon dioxide are released during one turn of the citric acid cycle.

Two carbons - from acetyl CoA-enter the citric acid cycle in each turn, and two carbon dioxide molecules are released. However, the carbon dioxide molecules don't actually contain carbon atoms from the acetyl CoA that just entered the cycle.

Instead, the carbons from acetyl CoA are initially incorporated into the intermediates of the cycle and are released as carbon dioxide only during later turns. After enough turns, all the carbon atoms from the acetyl group of acetyl CoA will be released as carbon dioxide.

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Answer:

B

Explanation:

I know but I can't answer well. We might to choose the best answer so the answer is possible to be B.

Answer:

Yes it's true ooooooooo

1.00 mol of water contains the most hydrogen atoms.

1 mol of water(H2O) contains 2 mol of hydrogen atoms

molar mass of hydrogen = 1.01 g/mol,

so 1 mol of water contains 21.01 = 2.02 g of hydrogen.

1 mol of Ammonia (NH3) contains 1 mol of hydrogen atoms

molar mass of hydrogen = 1.01 g/mol,

so 1 mol of ammonia contains 11.01 = 1.01 g of hydrogen.

hydrogen in 10.0 g of water  = 4.83 ×[tex]10^(22)[/tex] hydrogen atoms

hydrogen in  15.00 g of ammonia = 1.48  ×[tex]10^(23)[/tex] hydrogen atoms.

1 mol of water contains the most hydrogen atoms. This is because water, chemically represented as H2O, contains two hydrogen atoms for every oxygen atom. While 1 mol of ammonia(NH3) contains 1 mol of hydrogen atoms, 1 mol of water contains 2 mol of hydrogen atoms.

Therefore, 1 mol of water contains more hydrogen atoms than 1 mol of ammonia, and that's why option 3 -1 mol of water contains the most hydrogen atoms out of the options provided.

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The pressure of C2H4 and N2 gas is 0.3 atm

Based on the information provided, it appears that C2H4 and CH4 are added to a mixture of CO and N2 and then exposed to excess oxygen. The resulting mixture is then placed in a rigid container at a constant volume, and the pressure of CO2 and H2O vapor is measured to be 0.9 atm and 0.8 atm, respectively.

If the number of moles of C2H4 and CH4 is equal, the sum of the pressure of C2H4 and N2 gas can be calculated by subtracting the pressure of CO2 and H2O vapor from the total pressure. Since the total pressure is 1 atm, the sum of the pressure of C2H4 and N2 gas is:

1 atm - 0.9 atm - 0.8 atm = 0.3 atm

It is worth noting that this answer is based on the information provided and any additional information or assumptions may affect the final result.

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ionic and polar compounds are highly soluble in water whereas the covalent and organic compounds are highly insoluble in water

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Answer 1

The average atomic mass in a.m.u of Element X given this information is 122.358.

Answer 2

Rutherford's experiment change the way scientists had previously viewed atomic structure as it provided insight into atomic structure.

Rutherford's experiment paved the way for subsequent changes up to and including the currently accepted quantum mechanical atomic model as his  model of the atom, the structure of the nucleus became more well-defined following the discovery of protons (1919) and neutrons (1932) as the particle constituents of the nucleus.

Answer 3

The percent abundance is related to the number fraction as fi = Pi/100  and used as in the formula written above in order to find average mass

Atomic structure refers to the structure of an atom comprising a nucleus (centre) in which the protons (positively charged) and neutrons (neutral) are present.

The average atomic mass in a.m.u of Element X given this information is ((121 * 43.2) + (123 * 53.1) + (129 * 3.70)) / 100

=5227.2 + 6531.3 + 477.3

=12235.8 / 100

122.358

Rutherford's experiment change the way scientists had previously viewed atomic structure as it provided insight into atomic structure, and Rutherford's model of the atom was proposed as a small, positive, massive nucleus contains the very vast majority of the mass of the entire atom with negatively charged electrons surrounding it at relatively large distances.

Rutherford's experiment paved the way for subsequent changes up to and including the currently accepted quantum mechanical atomic model as his  model of the atom, the structure of the nucleus became more well-defined following the discovery of protons in 1919 and neutrons in 1932 as the particle constituents of the nucleus.

It was during the 1920s that a "wave mechanical model" came along through the work of several physicists most importantly de Broglie, Heisenberg, and Schrodinger) and Bohr's concept of electrons "orbiting" the nucleus was abandoned in favor of "orbitals" which are more abstract probabilistic representations of electronic structure within an atom.

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The elements and compounds present after a chemical reaction are called the products.

Answer:

yes, odor is classified as a physical property

Explanation:

Zn will replace the metal in the ionic compound LiF . false

What is metal ?

Metal is a hard material composed of a variety of elements, such as iron, aluminum, nickel, zinc, copper, lead, tin, and others. Metals are malleable, ductile, and generally have high electrical and thermal conductivity.

Metals can be polished to a shine and are often used in a variety of applications such as jewelry, construction, manufacturing, and many more. Metals are also used in many industries including automotive, aerospace, and medical. Metal is a durable and versatile material that is used for a variety of applications, from industrial to decorative.

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You would observe that the rock absorbs heat more quickly than the water and releases it more slowly. The rock will reach room temperature more quickly if you let them cool.

The majority of solar radiation that hits water's surface is reflected back into the atmosphere. Given that land absorbs more solar radiation, both the land's surface and the vegetation it supports retain more heat.

Water absorbs and releases heat more slowly than land because its specific heat is higher than that of dry soil. Due to the high heat capacity of water, large bodies of water often tend to moderate the temperature of neighboring land.

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Laura could use a few different methods to determine which beakers contain pure water and which contain solutions. One method is to test the boiling point of each liquid. Pure water boils at 100 degrees Celsius at standard pressure. If the liquid in a beaker boils at a temperature higher than 100 degrees Celsius, it is likely a solution and not pure water. Another method is to test the freezing point of each liquid. Pure water freezes at 0 degrees Celsius at standard pressure. If the liquid in a beaker freezes at a temperature other than 0 degrees Celsius, it is likely a solution and not pure water.

Another method is through density test. Pure water has a density of 1g/cm³ at 4°C. Laura can use a hydrometer, which is an instrument that measures the density of a liquid to check if the density of the liquids in the beakers is equal to 1g/cm³. If it is not, then it is not pure water.

Additionally, Laura could also test the conductivity of the liquids. Pure water is a poor conductor of electricity, whereas solutions can conduct electricity. Laura could use a conductivity meter to check the conductivity of the liquids. If a liquid conducts electricity, then it is likely a solution and not pure water.

Finally, Laura could also use a refractometer, which measures the refractive index of the liquid. The refractive index of pure water is 1.333 and any deviation from this value indicates the presence of dissolved solutes.

It's important to notice that no single test can confirm that a liquid is pure water, but a combination of tests can give us a strong indication of it.

Answer:

it decreases land temperature near the ocean

In general, ionization energy increases across a period and decreases down a group. Across a period, effective nuclear charge increases as electron shielding remains constant.

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