Answer:
I think we will know a lot more about the universe and the things around us. We may also know a lot more about other planets, such as Mars and Saturn, and we might also know a lot more about other stars in the universe.
Explanation:
The heat capacity of liquid water is 4.18 J/g·°C and the heat of vaporization is 40.7 kJ/mol. How many kilojoules of heat must be provided to convert 1.00 g of liquid water at 67°C into 1.00 g of steam at 100°C?
Answer:
The correct answer would be - 2.4KJ or, 2400J
Explanation:
Given:
heat capacity of liquid water - 4.18 J/g·°C
heat of vaporization - 40.7 kJ/mol
Mass of water = 1g
Moles of water = mass/molar mass
= 1g/18.016g
= 0.055 moles
Then,
Total heat required = q1(to raise the temperature to 100) + q2(change from the liquid phase to gas/steam)
= m *s*dt + moles * heat of vaporization
= (1g * 4.18 j/gc * (100-67)) + 0.055* 40.7 KJ
= 137.94J + 2.26KJ
=0.138KJ + 2.26KJ
=2.4KJ or, 2400J
Thus, the correct answer would be - 2.4KJ or, 2400J
An unknown element, X, reacts with oxygen to form two oxides with the general formula X_2O_3 and X_2O_5. The pure element is strongly paramagnetic, and the oxides are amphoteric. Which of the following elements could be represented by X?a) Scb) Bc) Nd) Sbe) S
Answer:
The unknown element is Sb
Explanation:
The first thing we must note is that the unknown element must be a member of group 15 in the periodic table. This is clear from the fact that the two oxides formed are X2O3 and X2O5. This implies that the unknown element X must have a valency of 3 or 5. This corresponds to our knowledge that the outermost electron configuration of group 15 elements is ns2np3. Hence, group fifteen elements can have a valency of 3 or 5.
The electronic configuration of antimony is; [Kr]4d10 5s2 5p3. This implies that the atom is paramagnetic since there are three unpaired 5p electrons. The oxides of antimony are known to be amphoteric. An ampohoteric oxide reacts with both acid and base, hence the answer.
Description (with words) of water just above melting temperature. What intermolecular forces do you expect to find in water in liquid state
Answer:
intermolecular dipole-dipole hydrogen bonds
Explanation:
Water is a polar molecule. Recall that the central atom in water is oxygen. The molecule is bent, hence it has an overall dipole moment directed towards the oxygen atom. Since it has a permanent dipole moment, we expect that it will show dipole-dipole interactions in the liquid state.
Similarly, water contains hydrogen and oxygen. Recall that hydrogen bonds are formed when hydrogen is covalently bonded to highly electronegative elements. Hence, water in the liquid state exhibits strong hydrogen bonding. The unique type of dipole-dipole interaction in liquid water is actually hydrogen bonding, hence the answer.
Without doing any calculations, match the following thermodynamic properties with their appropriate numerical sign for the following endothermic reaction. 2N2(g) + O2(g)2N2O(g) Clear All > 0 Hrxn < 0 Srxn = 0 Grxn > 0 low T, < 0 high T Suniverse < 0 low T, > 0 high T
Answer:
∆H > 0
∆Srxn <0
∆G >0
∆Suniverse <0
Explanation:
We are informed that the reaction is endothermic. An endothermic reaction is one in which energy is absorbed hence ∆H is positive at all temperatures.
Similarly, absorption of energy leads to a decrease in entropy of the reaction system. Hence the change in entropy of the reaction ∆Sreaction is negative at all temperatures.
The change in free energy for the reaction is positive at all temperatures since ∆S reaction is negative then from ∆G= ∆H - T∆S, we see that given the positive value of ∆H, ∆G must always return a positive value at all temperatures.
Since entropy of the surrounding= - ∆H/T, given that ∆H is positive, ∆S surrounding will be negative at all temperatures. This is so because an endothermic reaction causes the surrounding to cool down.
Which of the following best describes a salt bridge? a) A pathway composed of salt water that ions pass through. b) A pathway between the cathode and anode in which ions are reduced. c) A pathway by which counterions can flow between the half-cells with the solutions in the half-cell completely mixing.
Answer: A
Explanation:
If 2 moles of helium undergo a temperature increase of 100 K at constant pressure, how much energy has been transferred to the helium as heat
Answer:
[tex]Q=4154J[/tex]
Explanation:
Hello,
In this case, the involved heat in this heating process is considered to be computed via:
[tex]Q=nCp\Delta T[/tex]
Whereas we assume a constant molar specific heat of helium which is 20.77 J/(mol*K), thus, the transferred energy in the form of heat turns out:
[tex]Q=2mol*20.77\frac{J}{mol*K} *100K\\\\Q=4154J[/tex]
Regards.
Turn on Write equation. What you see is an equation that shows the original uranium atom on the left. The boxes on the right represent the daughter product—the atom produced by radioactive decay—and the emitted alpha particle.
Answer:
Uranium-238 undergoes alpha decay to form Thorium-234 as daughter product.
Explanation:
Alpha decay is indicative of loss of the equivalents of a helium particle emission. The reaction equation for this reaction is shown below:
[tex]_{92} ^{238} U_{}[/tex]→ [tex]_{90} ^{234} Th_{} + _{2} ^{4} He_{}[/tex]
I hope this explanation is clear and explanatory.
Balance the following equations: (c) H2(g)+I2(s)⟶HI(s)H2(g)+I2(s)⟶HI(s)
Answer: [tex]H_2(g)+I_2(g)\rightarrow 2HI(s)[/tex]
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
Thus in the reactants, there are 2 atoms of hydrogen and 2 atoms of iodine .Thus there has to be 2 atoms of hydrogen and 2 atoms of iodine in the product as well. Thus a coefficient of 2 is placed in front of HI.
The balanced chemical reaction is:
[tex]H_2(g)+I_2(g)\rightarrow 2HI(s)[/tex]
A 5.22 × 10−3−mol sample of HY is dissolved in enough H2O to form 0.088 L of solution. If the pH of the solution is 2.37, what is the Ka of HY?
Answer:
3.07 × 10⁻⁴
Explanation:
Step 1: Calculate the concentration of H⁺
We will use the definition of pH.
[tex]pH = -log [H^{+} ]\\\[ [H^{+} ] = antilog -pH = antilog -2.37 = 4.27 \times 10^{-3} M[/tex]
Step 2: Calculate the concentration of HY
5.22 × 10⁻³ mol of HY are dissolved in 0.088 L. The concentration of the acid (Ca) is:
[tex]Ca = \frac{5.22 \times 10^{-3} mol }{0.088L} = 0.0593M[/tex]
Step 3: Calculate the acid dissociation constant (Ka)
We will use the following expression.
[tex]Ka = \frac{[H^{+}]^{2} }{Ca} = \frac{(4.27 \times 10^{-3} )^{2} }{0.0593} = 3.07 \times 10^{-4}[/tex]
Calculate the free energy of formation of NaBr(s) given the following information: NaBr(s) → Na(s) + 1/2Br2(l), ∆G° = 349 kJ/mol
The given question is incomplete, the complete question is:
Calculate the free energy of formation of NaBr(s) given the following information: NaBr(s) → Na(s) + 1/2Br2(l), ΔG° = 349 kJ/mol
A) –309 kJ/mol
B) –329 kJ/mol
C) None of the above
D) –349 kJ/mol
E) –369 kJ/mol
Answer:
The correct answer is option D, that is, -349 kJ/mol.
Explanation:
Based on the given information, the reaction is:
NaBr (s) ⇔ Na (s) + 1/2 Br₂ (l), the ΔG° of the reaction given is 349 kJ per mole. In the given question, it is clearly mentioned that there is a need to determine the free energy of the formation of NaBr. Thus, there is a need to keep Na (s) and Br₂ (l) at the reactant side and NaBr (s) at the product side.
Therefore, there is a need to reverse the reaction and change the sign on ΔG.
Now the reaction will become,
Na (s) + 1/2 Br₂ (l) ⇔ NaBr (s), and the ΔG° will now become -349 kJ per mole. Hence, -349 kJ per mole is the free energy of the formation of NaBr (s).
Question 11: How does the energy of a photon emitted when the electron moves from the 3rd orbital to the 2nd orbital compare to the energy of a photon absorbed when the electron moves from the 2nd orbital to the 3rd orbital?
Answer:
Explanation:
The energy of a photon emitted when the electron moves from the 3rd orbital to the 2nd orbital is exactly same as the energy of a photon absorbed when the electron moves from the 2nd orbital to the 3rd orbital
Magnesium oxide can be produced by heating magnesium metal in the presence of oxygen. When 10.1 g of Mg reacts with 10.5 g of O2, 11.9 g of MgO are collected.
a) Write the balanced equation for this reaction, including all states of matter.
b) What is the limiting reactant in this reaction?
c) What is the theoretical yield for this reaction?
d) What is the percent yield for this reaction?
Answer:
A. 2Mg(s) + O2(g) —> 2MgO(s)
B. Mg is the limiting reactant.
C. Theoretical yield of MgO is 16.83g.
D. The percentage yield is 70.7%
Explanation:
A. The balanced equation for the reaction. This is given below:
2Mg(s) + O2(g) —> 2MgO(s)
B. Determination of the limiting reactant.
First, we shall determine the mass of Mg and O2 that reacted and the mass of MgO produced from the balanced equation. This is illustrated below:
Molar mass of Mg = 24g/mol
Mass of Mg from the balanced equation = 2 x 24 = 48g.
Molar mass of O2 = 16x2 = 32g/mol.
Mass of O2 from the balanced equation = 1 x 32 = 32g
Molar mass of MgO = 24 + 16 = 40g/mol
Mass of MgO from the balanced equation = 2 x 40 = 80g
Summary:
From the balanced equation above,
48g of Mg reacted with 32g of O2 to produce 80g of MgO.
Now, we can obtain the limiting reactant as follow:
From the balanced equation above,
48g of Mg reacted with 32g of O2.
Therefore, 10.1g of Mg will react with = (10.1 x 32)/48 = 6.73g of O2.
From the calculations made above, we can see that only 6.73g out of 10.5g of O2 given is needed to react completely with 10.1g of Mg.
Therefore, Mg is the limiting reactant and O2 is the excess reactant.
C. Determination of the theoretical yield of MgO.
The limiting reactant is used in this case as it will produce the maximum yield of the reaction since all of I is used up in the reaction.
The theoretical yield can be obtain as illustrated below:
From the balanced equation above,
48g of Mg reacted to produce 80g of MgO.
Therefore, 10.1g of Mg will react to produce = (10.1 x 80)/48 = 16.83g of MgO.
Therefore, the theoretical yield of MgO is 16.83g.
D. Determination of the percentage yield.
This is illustrated below:
Actual yield of MgO = 11.9g
Theoretical yield of MgO = 16.83g
Percentage yield =..?
Percentage yield = Actual yield /Theoretical yield x 100
Percentage yield = 11.9/16.83 x 100
Percentage yield = 70.7%
Devise a detailed experimental procedure to purify ~ 20 grams of benzoic acid that is contaminated with sodium chloride. Justification of the steps (including solubility calculations) that are included in the procedure. In other words, explain why the steps are being included.
Answer:
Based on the difference in solubility one can perform the process of purification of the benzoic acid contaminated with sodium chloride. The benzoic acid does not get soluble in cold water, while the sodium chloride is soluble in cold water.
Thus, for separation, the supplementation of cold water can be done into the mixture in the experiment of purifying benzoic acid from sodium chloride. In the process, the mixture is placed on the ice bath and is stirred well, in the end, the solution is filtered. The filtrate contains sodium chloride and on the filter paper pure benzoic acid is collected.
Can a catalyst change an exothermic reaction into an endothermic reaction or vice versa? Please explain your answer.
Answer:
A catalyst cannot change an exothermic reaction into an endothermic reaction or vice versa.
Explanation:
Catalyst is basically a substance that enables a chemical reaction to occur at a faster rate as compared to the reaction without catalysis. It lowers the activation energy and temperature for a chemical reaction and a catalyst itself does not goes through any permanent chemical change. This means it does not get used in the process.
Exothermic and endothermic are the chemical reaction. Exothermic reactions absorb energy. This energy is absorbed in the form of heat. When the energy is released in the form of heat then this reaction is called endothermic. So one absorbs the heat and the other releases it.
As we know that the catalyst does not undergo change at the end of the reaction so the energy or heat whether is absorbed or emitted or you can say whether the reaction is exothermic or endothermic, the total energy stays unchanged during the reaction. So with and without a catalyst, if both have same reactants and products and the difference in enthalpy between products and reactants will be the same.
What is the name of Mn(CO3)2
Answer:
Mn is manganese and CO₃ is carbonate. Since the charge for CO₃ is -2 and the subscript is 2, the charge of Mn must be +4 so the answer is manganese (IV) carbonate.
Manganese (IV) carbonate is the name of Mn(CO[tex]_3[/tex])[tex]_2[/tex]. The only names used to identify salts are those of the cation or the anion.
The chemical formula of the anion (such as chloride or acetate) comes first in the name of a salt, which is followed with the identity of the cation (such as sodium or ammonium). They are created when acids and bases react, and they are always composed of either metal cations or cations made of ammonium. Manganese is Mn, and carbonate is CO[tex]_3[/tex]. The solution equals manganese (IV) carbonate since the charge for CO[tex]_3[/tex] is -2 but the subscript is 2, meaning that the charge of Mn has to be +4.
To know more about naming of salt, here:
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Which best describes the act of using senses or tools to gather information? creating a hypothesis making an observation summarizing the results recording the measurements
Answer:
B - Making an Observation
Explanation:
Making an observation best describes the act of using senses or tools to gather information. Therefore, option B is correct.
What are senses in the scientific method?The five senses—sight, taste, touch, hearing, and smell—gather data about our surroundings that the brain interprets. Based on prior experience (and subsequent learning), as well as by combining the data from each sensor, we make sense of this information.
Information gleaned from your five senses is referred to as an observation. These are smell, taste, touch, hearing, and sight. When you see a bird or hear it sing, you notice it.
The term observation, which is also used to sense five aspects of the world including vision, taste, touch, smell, and hearing, is used to describe utilizing the senses to examine the world, employing tools to take measurements, and looking at prior research findings.
Thus, option B is correct.
To learn more about the scientific method, follow the link:
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a ______ consumer is a heterotroph that directly eats an autotroph. A primary B. Quaterany C tertiary D secondary
Calculate the pH for the following 1.0M weak acid solutions:a. HCOOH Ka = 1.8 x 10-4 [
Answer: pH=2.38
Explanation:
To calculate the pH, let's first write out the equation. Then, we will make an ICE chart. The I in ICE is initial quantity. In this case, it is the initial concentration. The C in ICE is change in each quantity. The E is equilibrium.
HCOOH ⇄ H⁺ + HCOO⁻
I 1.0M 0 0
C -x +x +x
E 1.0-x x x
For the steps below, refer to the ICE chart above.
1. Since we were given the initial of HCOOH, we can fill this into the chart.
2. Since we were not given the initial for H⁺ and HCOO⁻, we will put 0 in their place.
3. For the change, we need to add concentration to the products to make the reaction reach equilibrium. We would add on the products and subtract from the reactants to equalize the reaction. Since we don't know how much the change in, we can use variable x.
4. We were given the Kₐ of the solution. We know [tex]K_{a} =\frac{product}{reactant}=\frac{[H^+][HCOO^-]}{[HCOOH]}[/tex].
5. The problem states that the Kₐ=1.8×10⁻⁴. All we have to so is to plug it in and to solve for x.
[tex]1.8*10^-^4 =\frac{x^2}{0.1-x}[/tex]
6. Once we plug this into the quadratic equation, we get x=0.00415.
7. The equilibrium concentration of [H⁺]=0.00415. pH is -log(H⁺).
-log(0.00415)=2.38
Our pH for the weak acid solution is 2.38.
When hydrocarbons are burned in a limited amount of air, both CO and CO2 form. When 0.430 g of a particular hydrocarbon was burned in air, 0.446 g of CO, 0.700 g of CO2, and 0.430 g of H2O were formed.
Required:
a. What is the empirical formula of the compound?
b. How many grams of O2 were used in the reaction?
c. How many grams would have been required for complete combustion?
Answer:
(a) The empirical formula of the compound is
m(CxHy) + m(O2) = m(CO) + m(CO2) + m(H2O).
(b) The grams of O2 that were used in the reaction is 1.146 g
(c) The amount of O2 that would have been required for complete combustion is 1.401 g.
Explanation:
a. m(CxHy) + m(O2) = m(CO) + m(CO2) + m(H2O)
(b) Using law of conservation of mass from above
m(O2) = m(CO) + m(CO2) + m(H2O) - m(CxHy)
m(O2) = 0.446 + 0.700 + 0.430 - 0.430
m(O2) = 1.146 g
The grams of O2 that were used in the reaction is 1.146 g
(c) for complete combustion, we need to oxidized CO to CO2
Then, 2CO +O2 = 2CO2
m(add)(O2) = M(O2)*¢(O2)/2 = M(O2) * {(m(CO))/(2M(CO))}
m(add)(O2) = 32 * {(0.446)/(2*28)} = 0.255 g
Note; Molar mass of O2 = 32, CO = 28
m(total)(O2) = m(O2) + m(add)(O2)
m(total)(O2) = 1.146 + 0.255 = 1.401 g
The amount of that grams would have been required for complete combustion is 1.401 g.
Note (add) and (total) were used subscript to "m"
Add distilled water to the beaker until the volume
totals 15 mL.
Record the amount of oil that dissolved.
Answer:
i guess oil never dissolve in water. As like dissolve like. water is polar so it dissolves only polar substances
Explanation:
Answer:
None
Explanation:
Answer on Edge 2022
A pentavalent cation atom has 20 and 15 neutrons as protons. Find the electron quantity and mass number respectively. (40 pts.) a) 20 and 15 b) 15 and 20 c) 15 and 35 d) 35 and 15 e) 10 and 20
Answer:
C.
Explanation:
Since the mass number is the number of protons and neutrons added together, the answer is 35. Since the questions are respectively electron quantity and mass number, the only answer choice with 35 as the second choice is C, so that is the correct answer.
Dissolving NaOH(s) in water is exothermic. Two calorimetry experiments are set up. Experiment 1: 2 g of NaOH are dissolved in 100 mL of water Experiment 2: 4 g of NaOH are dissolved in 200 mL of water Which of the following statements is true?a. both temperature changes will be the sameb. the second temeprature change will be approximately twice the firstc. the second temperature change will be approximately four times the firstd. the second temperature change will be approximately one-half of the firste. the second temperature change will be approximately one-fourth the first
Answer:
a. both temperature changes will be the same
Explanation:
When sodium hydroxide (NaOH) is dissolved in water, a determined amount is released to the solution following the equation:
Q = m×C×ΔT
Where Q is the heat released, m is the mass of the solution, C is the specific heat and ΔH is change in temperature.
Specific heat of both solutions is the same (Because the solutions are in fact the same). Specific heat = C.
m is mass of solutions: 102g for experiment 1 and 204g for experiment 2.
And Q is the heat released: If 2g release X heat, 4g release 2X.
Thus, ΔT in the experiments is:
Experiment 1:
X / 102C = ΔT
Experiment 2:
2X / 204C = ΔT
X / 102C = ΔT
That means,
a. both temperature changes will be the same
What do we call temperature changes caused by changes in air pressure?
Answer:
Fronts
Explanation:
For example, there are hot and cold fronts which cause the air to become warmer or cooler in a specific region!
Hope this helps! Please mark as brainiest!
how do you fight off ADHD medication
Answer:A medication break can ease side effects. A lack of appetite, weight loss, sleep troubles, headaches, and stomach pain are common side effects of ADHD medication.
Explanation: It may boost your child’s growth. Some ADHD medications can slow a child’s growth in height, especially during the first 2 years of taking it. While height delays are temporary and kids typically catch up later, going off medication may lead to fewer growth delays.
It won’t hurt your child. Taking a child off ADHD medication may cause their ADHD symptoms to reappear. But it won’t make them sick or cause other side effects.
Which of the following would have a fixed shape and volume? (3 points) nitrogen gas solid wood liquid water neon gas
Answer:
Solid Wood
Explanation:
Wood is like a solid block, whereas gases flow freely and liquids spread to fill the shape of their container.
Please let me know if I misunderstood the question, by the way.
A package contains 1.33 lb of ground round. If it contains 29% fat, how many grams of fat are in the ground round? The book is saying 91g I keep getting 175g. Can someone please explain?
Answer:
To obtain the grams of fat that the ground round has, knowing that it weighs 1.33 pounds we must pass this value to grams. Since 1 pound equals 453.59 grams, 1.33 pounds equals 603.27 (453.59 x 1.33).
Now, to obtain 29 percent of 603.27, we must make the following calculation: 603.27 / 100 x 29, which gives a total of 174.94 grams.
In this way, your reasoning is correct and it is probably a mistake in the book.
tank contains helium gas at 490 mm Hg, nitrogen gas at 0.75 atm and neon at 520 torr. What is the total pressure in atm? 2.1 atm 0.55 atm 1.5 atm 5.1 atm 51 atm
Answer:
2.1 atm
Explanation:
Before we get the total pressure, we have to ensure all the gases have the same pressure unit.
Nitrogen gas = 0.75 atm
Helium = 490mmHg
To convert mmHg to atm;
760 mmHg = 1 atm
490 = x
x = 460 / 760 = 0.645 atm
Neon = 520 torr
Converting torr to atm;
760 torr = 1 atm
520 torr = x
x = 520 / 760 = 0.684 atm
The total pressure is then given as;
0.75 + 0.684 + 0.645 = 2.1 atm
"Calculate the pH during the titration of 20.00 mL of 0.1000 M HF(aq) with 0.2000 M NaOH(aq) after 9.4 mL of the base have been added. Ka of hydrofluoric acid
Answer:
The answer is " 10.39"
Explanation:
Calculating acid moles:
[tex]= 0.02000 \ L \times 0.1000 \ M \\\\= 0.002000[/tex]
Calculating NaOH moles:
[tex]= 0.02012 \ L \times 0.1000 \ M \\\\= 0.002012[/tex]
calculating excess in OH- Moles:
[tex]= 0.002012 - 0.002000\\\\=0.000012[/tex]
calculating total volume:
[tex]= 20.00 + 20.12\\\\ = 40.12 mL \\\\= 0.04012 L[/tex]
[tex][OH-]= \frac{0.000012} { 0.0472}[/tex]
[tex]=0.00025 M[/tex]
[tex]pOH = - \log 0.00025[/tex]
= 3.6
[tex]pH = 14 - pOH[/tex]
= 10.39
If the pKaof HCHO2is 3.74 and the pH of an HCHO2/NaCHO2solution is 3.11, which of the following is true?
A. [HCHO2] < [NaCHO2]
B. [HCHO2] = [NaCHO2]
C. [HCHO2] << [NaCHO2]
D. [HCHO2] > [NaCHO2]
E. It is not possible to make a buffer of this pH from HCHO2 and NaCHO2
Answer:
D. [HCHO₂] > [NaCHO₂]
Explanation:
Formic acid, HCHO₂, is a weak acid that, in presence of its conjugate base, NaCHO₂ (CHO₂⁻), produce a buffer following H-H equation:
pH = pKa + log [CHO₂⁻] / [HCHO₂]
As pKa of the acid is 3.74 and pH of the solution is 3.11:
3.11 = 3.74 + log [CHO₂⁻] / [HCHO₂]
-0.63 = log [CHO₂⁻] / [HCHO₂]
0.2344 = [CHO₂⁻] / [HCHO₂]
A ratio [CHO₂⁻] / [HCHO₂] < 1, means:
[HCHO₂] > [CHO₂⁻]Identify the elements that correspond to the following generalized electron configuration: (noble gas]ns2(n − 2) f6
Express your answer as the element symbol. If there is more than one answer, separate them by a comma.
Answer:
Samarium:
Electron configuration:
Samarium
Explanation:
Samarium is a chemical element that belongs to the lanthanoid series. The lanthanoids are the chemical elements that follow lanthanum. They are all known to possess 4f orbitals. The 4f electrons are found in the antepenultimate shell of the elements of the lanthanoid series and they do not take part in chemical bonding. They are neither removed in bonding nor do they take part in crystal field stabilization of lanthanoid complexes.
The electronic configuration of samarium is; 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f6 while the condensed, short hand electronic configuration is [Xe] 4f6 6s2. This corresponds to (noble gas]ns2(n − 2) f6 as required by the question, hence the answer provided above.