Calculate The Difference Between The Numbers.(9.543 X 10^-5) - (2.544 X 10^-2) (2024)

Explanation:

To help us determine which element results from the reaction between NH3 and BF3, we can identify the valence states of the atoms that participate in the reaction and how many bonds they can form.

We have for each element the valence electrons and the bonds that they can form in such a way that they complete 8 electrons in the last energy level:

*N ---> 3 valence electrons, can form maximum 5 bonds

*H ---> 1 valence electrons, can form maximum 1 bond

*B ---> 5 valence electrons, can form maximum 3 bond

*F ---> 9 valence electrons, can form maximum 1 bond, if it lose one electron

Now we compare the options they give us with the maximum possible links that each element can form.

A and B have a hydrogen atom that forms two bonds, this is not possible since it does not have enough electrons to do so. So we discard A and B.

In C we have a fluorine atom forming two bonds, this is not possible since it can only form a bond by donating its electron.

Option D has the correct links for each element, so the answer will be D.

Answer: D

Answer:

[tex]\begin{gathered} a)\text{ 111 moles} \\ b)\text{ 139.02 moles} \\ c)\text{ C}_6H_4Cl_2 \\ d)\text{ 111 moles} \end{gathered}[/tex]

Explanation:

a) From the balanced equation of reaction:

2 moles of dichlorobenzene produced 12 moles of carbon dioxide

18.5 moles of dichlorobenzene will produce x moles of carbon dioxide

To get the value of x, we have it that:

[tex]\begin{gathered} 2\text{ }\times x\text{ = 18.5 }\times12 \\ x\text{ = }\frac{18.5\times12}{2}\text{ = 111 moles} \end{gathered}[/tex]

b) From the equation of reaction:

13 moles of oxygen produced 12 moles of carbon dioxide

150.6 moles of oxygen will produce x moles of carbon dioxide

To get the value of x, we have it that:

[tex]\begin{gathered} 13\text{ }\times\text{ x = 12 }\times150.6 \\ x\text{ = }\frac{12\times150.6}{13} \\ x\text{ = 139.02 moles} \end{gathered}[/tex]

c) The limiting reagent would be the reactant that produces less of the product

dichlorobenzene produces less and thus, it is the limiting reactant

d) To get the theoretical yield, we multiply the number of moles of the limiting reagent by the ratio between the product and the limiting reagent

We have the number of moles of the limiting reagent by the mole ratio

We have the number of moles of the limiting reagent as 18.5 mol and the mole ratio as (product to reactant = 12:2 = 6 to 1)

We have the theoretical yield as:

[tex]6\text{ }\times\text{ 18.5 = 111 mol}[/tex]

First we balance the metals P:phosphorus

[tex]\text{ HClO}_4\text{ + P}_2\text{O}_5\text{ }\rightarrow\text{ Cl}_2\text{O}_7\text{ + 2HPO}_3[/tex]

then we balance the non-metals Cl:chlorine

[tex]\text{ 2HClO}_4\text{ + P}_2\text{O}_5\text{ }\rightarrow\text{ Cl}_2\text{O}_7\text{ + 2HPO}_3[/tex]

Then we balance the hydrogens and oxygens

If we look at the hydrogens and oxygens they are already balanced because there are 2 hydrogens in the reactants and 2 hydrogens in the products. Similarly, There are 13 oxygens in the reactants and 13 oxygens in the products.

The answer is:

[tex]2\text{ HClO}_4\text{ + P}_2\text{O}_5\text{ }\rightarrow\text{ Cl}_2\text{O}_7\text{ + 2HPO}_3[/tex]

In this question, we have a reaction between two compounds, Sodium sulfide and Hydrochloric acid. This reaction will have the following chemical formulas:

Na2S (aq) + 2 HCl (aq) --> H2S (g) + 2 NaCl (aq)

This is the complete and balanced reaction between Sodium sulfide and Hydrochloric acid, the correct answer will be the 1st option

We know this:

Mass of hydrate = 5 g

Mass of anhydrous = 3 g

To find the mass of water that is heated off, we hate to do this:

Mass of hydrate - Mass of Anhydrous = mass of water driven off

5 g - 3 g = 2 g of water driven off

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Answer:

Mass of water = 2 g

We have to know this:

Solution here = HCl (solute) + Water (solvent)

Solution 1)

Volume 1 (V1)= 50 mL

Concentration 1 (M1) = 0.2 M

We add 200 mL of water into Solution 1, so we will have a diluted solution which is Solution 2.

Solution 2)

Volume 2 (V2, be careful with the dilution) = 50 mL + 200 mL (added) = 250 mL

Concentration 2 (M2) = Need to be found

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The formula we use to calculate concentration 2 is:

V1 x M1 = V2 x M2, we clear M2 from here and we get to:

M2 = (V1 x M1) / V2 = (50 mL x 0.2 M) / 250 mL = 0.04 M

M2 = 0.04 M ( we can say that it is right because when we add water, concentration of the solution will decrease)

Answer: M2 = 0.04 M (mol/L)

On of the definitions of acids and bases in acid/base reactions is that the acid is the species that donates a H⁺, while the base is the species that receives it.

As we can see, in the reaction the species HC₂H₃O₂ loses its H⁺ and pair up with Na⁺, so it is the acid, because it is donating the H⁺ in the reaction.

NaOH, on the other hand, is receiving the H⁺ and turning into H₂O, while its Na⁺ pairs with the other. This means that NaOH is the base, since it is receiving the H⁺.

The conjugate acid is the acid that is formed in the reaction by the species that received the H⁺, that is, the base reactant receives the H⁺ and turn itself into its conjugate acid.

The conjugate base, on the other hand, is the species formed by the acid after it donated the H⁺.

The acid, HC₂H₃O₂, turned into NaC₂H₃O₂, so this is the conjugate base.

The base, NaOH, turned into H₂O, so this is the conjugate acid.

Thus, we have:

Acid: HC₂H₃O₂

Base: NaOH

Conjugate Acid: H₂O

Conjugate Base: NaC₂H₃O₂

Explanation:

Please, look at the next drawing:

Answer: 1 dL = 100 mL

The question requires us to calculate the molar concentration of an acetic acid solution, given that it was necessary 36.4 mL of a 0.100 M NaOH solution to neutralize 50.0 mL of the acid.

The following information was provided by the question:

concentration of NaOH solution = C(OH-) = 0.100 M

volume of NaOH solution = V(OH-) = 36.4 mL

volume of CH3COOH solution = V(H+) = 50.0 mL

Acetic acid (CH3COOH) and sodium hydroxide (NaOH) react according to the following reaction:

[tex]\text{CH}_3COOH_{}+NaOH_{}\to CH_3COONa+H_2O[/tex]

Considering that at the equivalent point the number of moles of acid (H+) is the same as the number of moles of base (OH-) and taking the stoichiometry of the reaction into consideratio (1 : 1), we can write:

[tex]At\text{ equivalent point}\to n_{H^+}n_{OH^-}\to n_{CH_3COOH}=n_{NaOH}[/tex]

We can also write the number of moles of a compound (n) in terms of its molar concentration and volume:

[tex]\begin{gathered} \text{molar concentration = }\frac{number\text{ of moles}}{\text{volume}}\to C=\frac{n}{V} \\ \\ n=C\times V \end{gathered}[/tex]

Thus, considering the equivalent point, we can say:

[tex]n_{CH_3COOH}=n_{NaOH}\to C_{CH_3COOH}\times V_{CH_3COOH}=C_{NaOH}\times V_{NaOH}[/tex]

Now, we can apply the values of volume and concentration provided by the question to the equation above and obtain the concentration of the acid:

[tex]\begin{gathered} C_{CH_3COOH}\times V_{CH_3COOH}=C_{NaOH}\times V_{NaOH} \\ C_{CH_3COOH}\times(50.0mL)=(0.100M)\times(36.4mL) \\ C_{CH_3COOH}=\frac{(0.100M)\times(36.4mL)}{(50.0mL)}=0.0728M \end{gathered}[/tex]

Therefore, the molar concentration of the acetic acid solution is 0.0728 M and the best option to answer this question is the third one.

Answer:

a. Decomposition

Explanation:

This is a decomposition reaction, because from one compound we obtain two differents compounds.

[tex]7.07\cdot10^{-6}\operatorname{kg}[/tex]

STEP-BY-STEP EXPLANATION:

Given information

Mass to be converted = 7.07 mg

Let x represents the converted mass in kg

[tex]\begin{gathered} \text{ Recall that, 1 mg is equivalent to 10}^{-6}kg \\ \text{ Since x is the converted mass in kg} \\ \text{Then}, \\ 1\text{ mg }\rightarrow10^{-6}\operatorname{kg} \\ 7.07\text{ mg }\rightarrow\text{ xkg} \\ \text{Cross multiply} \\ 1\cdot\text{ x = 7.07 }\cdot10^{-6} \\ x\text{ = 7.07 }\cdot10^{-6}\text{ }kg \end{gathered}[/tex]

Therefore, 7.07 mg is 7.07 x 10^-6 kg

Answer and Explanation

we are given the combustion reaction between oxygen and butane

the balanced reaction equation is:

2C₄H₁₀ + 13O₂ => 8CO₂ + 10H₂O

from the balance chemical equation, we see that 2 moles of butane react with 13 moles of oxygen.

if we have 5.5 moles of oxygen the we need:

2/13 x 5.5 = 0.85 moles of butane

the grams of carbon dioxide that will be produced if we react 3.5 moles of oxygen can be determined by first looking at the mole ratio from the balanced equation. we see that 13 moles of oxygen produce 8 moles of carbon dioxide

therefor the number of moles of carbon dioxide that will form from 3.5 moles of oxygen will be

8/13 x 3.5 = 2.15 moles

if we have 2.15 moles of carbon dioxide, we can determine the mass using the following reaction equation:

mass = n x m

where n is moles

M is molar mass of carbon dioxide

mass = 2.15moles x 44.01g/mole

= 94.62 grams

94.62 grams of carbon dioxide will be formed

Chemistry => Solutions => Dilution

A solution is a mixture of two or more substances. In this case, we have a solution of acid in water. For dilutions we can apply the following equation:

[tex]C_1V_1=C_2V_2[/tex]

Where,

C1 is the initial concentration, 45%

V1 is the initial volume of the solution, 70mL

C2 is the final concentration, 30%

V2 is the final volume of the solution, unknown

Now, we clear V2 and replace the known data:

[tex]\begin{gathered} V_2=\frac{C_1V_1}{C_2} \\ \\ V_2=\frac{45\%\times70mL}{30\%} \\ \\ V_2=105mL \end{gathered}[/tex]

The final volume of the solution will be 105 mL. The water should be added will be:

[tex]\begin{gathered} H_2O=V_2-V_1 \\ \\ H_2O=105mL-70mL \\ \\ H_2O=35mL \end{gathered}[/tex]

Answer: To dilute the solution from 45% to 30%, should be added 35 mL of water.

Answer:

0.1583moles

Explanations:

According to ideal gas equation;

[tex]PV=nRT[/tex]

where:

• P is the ,pressure, = 157kPa = 1.55atm

,

• V is the volume = 3L

,

• R is the Gas constant = 0.08205Latm/molK

,

• T is the temperature = 85 + 273 = 358K

Required

n is the number of moles

Substitute the given parameters

[tex]\begin{gathered} n=\frac{PV}{RT} \\ n=\frac{1.55\times3}{0.08205\times358} \\ n=\frac{4.65}{29.3739} \\ n=0.1583moles \end{gathered}[/tex]

Hence the number of moles of CO that are present in the sample is 0.1583moles

Answer:

K, Rb, Sr, Sn

Explanations:What is electronegativity?

This is the ability of an atom or element to attract electron to itself. In the periodic table, eletronegativity decreses down the groups, and increases from left to right across periods.

According to the question, we are to rank the following elements according to their increasing electronegativity that is from the least electronegative to more electronegative element.

Therefore the choice that ranks the elements in order of increasing electronegativity is K, Rb, Sr, Sn

Answer:

Explanation:

Here, we want to answer some questions about titration

We shall be answering questions for sample 1 as follows

a) Mass of KHP in sample 1

That would be the difference between mass of beaker + KHP after first sample taken minus mass of beaker + KHP before sample taken

Mathematically, we have that as:

[tex]4.5155\text{ - 4.0032 = 0.5123 g}[/tex]

b) Moles of KHP

Mathematically, we have that as:

[tex]\begin{gathered} \frac{mass\text{ of KHP}}{molar\text{ mass of KHP}} \\ \\ molar\text{ mass of KHP is 204.22 g/mol} \\ \\ Number\text{ of moles:} \\ \frac{0.5123}{204.22}\text{ = 0.0025 mole} \end{gathered}[/tex]

c) Volume of NaOH utilized

We can get that from the given table

We have the value as 22.75 mL/1000 = 0.2275 L

d) Molarity of NaOH from sample 1

Let us write the equation of reaction;

[tex]KHP\text{ + NaOH }\rightarrow\text{ KNAP + H}_2O[/tex]

We have the general equation to use as:

[tex]\frac{C_aV_a}{n_a}\text{ = }\frac{C_bV_b}{n_b}[/tex]

But we need to calculate the concentration of the acid

We have the volume of acid used as 22.86 - 0.11 = 22.75 mL = 0.2275 L

The molarity would be:

[tex]\frac{mass\text{ of KHP}}{molar\text{ mass of KHP}}\text{ }\times\text{ }\frac{1}{vol\text{ in L}}[/tex][tex]\frac{0.0025}{0.2275}\text{ = 0.011 M}[/tex]

From the dilution equation above:

Ca is KHP molarity = 0.011 M

Va is KHP volume = 0.2275 L

Cb is NaOH molarity = ?

Vb is NaOH volume = 0.2275

na is the number of moles of acid in the balanced equation which is 1

nb is the number of moles of base is balanced equation which is 2

Substituting the values:

[tex]\begin{gathered} \frac{0.011\text{ }\times\text{ 0.2275}}{1}\text{ = }\frac{C_b\times0.2275}{1} \\ \\ C_b\text{ = 0.011 M} \end{gathered}[/tex]

Answer:

The resulting concentrations at equilibrium are:

[PCl5] = 0.168 M

[PCl3] = 0.0595 M

[Cl2] = 0.0595 M

Explanation:

The question requires us to calculate the concentrations of PCl3 and Cl2, given that 0.670 moles of PCl5 were placed in a 4.00 L container and the equilibrium constant of the following reaction is 0.0211 M:

[tex]PCl_{5(g)}\rightleftarrows PCl_{3(g)}+Cl_{2(g)}[/tex]

We can solve this problem using the equilibrium constant expression, considering that the concentration of PCl3 and Cl2 at the equilibrium will be the same (note that they present the same stoichiometric coefficient).

We can write the expression for the equilibrium constant as:

[tex]K=\frac{[PCl_3\rbrack\times[Cl_2\rbrack}{[PCl_5\rbrack}[/tex]

Considering that [PCl3] = [Cl2] = x, we can rearrange this expression to calculate x:

[tex]x^2=K\times[PCl_5\rbrack\rightarrow x=\sqrt[x]{K\times[PCl_5\rbrack}[/tex]

The concentration of PCl5 can be obtained from the number of moles given (0.670 moles) and the volume of the container (4.00L):

[tex][PCl_5\rbrack=\frac{0.670mol}{4.00L}=0.168mol/L=0.168M[/tex]

Now, applying the values of K (0.0211M) and [PCl5] (0.168M) to the expression we wrote above, we'll have:

[tex]\begin{gathered} \begin{equation*} x=\sqrt[x]{K\times[PCl_5\rbrack} \end{equation*} \\ \\ x=\sqrt[2]{0.0211M\times0.168M}=0.0595M \end{gathered}[/tex]

Therefore, the resulting concentrations at equilibrium are:

[PCl5] = 0.168 M

[PCl3] = 0.0595 M

[Cl2] = 0.0595 M

ANSWER

[tex]The\text{ wavelength of the radiation = 8.57 }\cdot10^{-3}m[/tex]

STEP-BY-STEP EXPLANATION:

What to find? The wavelength of the electromagnetic radiation.

Given parameters

Frequency of the electromagnetic radiation = 3.5 * 10^10Hz

To find the wavelength of the electromagnetic radiation, we need to apply the below formula

[tex]\begin{gathered} C\text{ = f }\cdot\text{ }\lambda \\ \text{Where} \\ C\text{ = sp}eed\text{ of light} \\ f\text{ = frequency of the electromagnetic radiation} \\ \lambda\text{ = wavelength of the electromagnetic radiation} \end{gathered}[/tex]

Note: The speed of light is given as 3 x 10^8 m/s

The next thing to do is to substitute the given parameters into the above formula

[tex]\begin{gathered} 3\cdot10^8\text{ = 3.5 }\cdot10^{10}\cdot\text{ }\lambda \\ \text{Divide both sides by 3.5 }\cdot10^{10} \\ \frac{3\cdot10^8}{3.5\cdot10^{10}}\text{ = }\frac{3.5\cdot10^{10}\lambda}{3.5\cdot10^{10}} \\ \lambda\text{ = }\frac{3\cdot10^8}{3.5\cdot10^{10}} \\ \lambda\text{ = }\frac{3}{3.5}\cdot10^{8\text{ - 10}} \\ \lambda\text{ = 0.857 }\cdot10^{-2} \\ \lambda\text{ = 8.57 }\cdot10^{-1}\cdot10^{-2} \\ \lambda\text{ = 8.57 }\cdot10^{-1-2} \\ \lambda\text{ = 8.57 }\cdot10^{-3}m \end{gathered}[/tex]

Answer:

76.04mL

Explanations

The formula for calculating the density of a substance is expressed as:

[tex]Density=\frac{Mass}{volume}[/tex]

60% m/m = 60 g of ethanol in 100 g of solution

Given that the density of ethanol = 789 kg/m³.

Convert the 60%m/m mass to kg to have;

mass of ethanol required = 0.06kg

Determine the volume

[tex]\begin{gathered} volume=\frac{mass}{density} \\ volume=\frac{0.06}{789} \\ volume=0.00007604m^3 \end{gathered}[/tex]

Convert cubic meters to mL

Since 1m³ = 10⁶mL, hence

0.00007604m³ = 0.00007604 * 10⁶

0.00007604m³ = 76.04mL

Hence the volume of ethanol that are in a 100 g of this hand sanitizer is 76.04mL

The molarity of 0.3 N potassium permanganate solution (KMnO₄) is 0.06 M.

What is the molarity of a solution?

The molarity of a solution is the number of moles of a substance present in a given volume of solution.

The normality of a solution is the number of gram or mole equivalents of solute present in one liter of a solution.

The normality and the molarity of a solution are related by the formula below;

Molarity = normality / mole equivalents

1 mole of KMnO₄ = 5 equivalents

Normality of KMnO₄ = 0.3 N

Molarity of KMnO₄= 0.3 / 5

Molarity of KMnO₄ = 0.06 M

Learn more about normality and molarity at: https://brainly.com/question/22817773

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First of all, let's define the concentration of the solution they give us. It tells us that the solution must be 1.3M, this is a measure of molarity that tells us the number of moles of solute (NaNO3) in 1 liter of solution.

So from this information, we can find the number of moles of NaNO3 and from there we can find the mass using the molar mass of NaNO3. Let's proceed to do the calculations, let's first find the necessary moles of NaNO3

[tex]\begin{gathered} \text{Mol NaNO}_3=GivenLsolution\times\frac{1.3molNaNO_3}{1Lsolution} \\ \text{Mol NaNO}_3=450.mLsolution\times\frac{1L}{1000mL}\times\frac{1.3molNaNO_3}{1Lsolution}=0.585molNaNO_3 \end{gathered}[/tex]

Now, the molar mass of NaNO3 is equal to 84.9947 g/mol, from the number of moles we can find the grams needed:

[tex]\begin{gathered} gNaNO_3=GivenmolNaNO_3\times\frac{MolarMass,gNaNO_3}{1molNaNO_3} \\ gNaNO_3=0.585molNaNO_3\times\frac{84.9947gNaNO_3}{1molNaNO_3}=49.7gNaNO_3 \end{gathered}[/tex]

Answer: for making 450.mL of a 1.3 M NaNo3 solution is needed 49.7 g of NaNO3

According to this reaction:

2ZnS(s) + 302 (g) ==> 2ZnO (s) + 2S02(g) AH= - 879 kJ/mol

We know that from 3 moles O2 the reaction releases 879 kJ/mol of energy. We want to know per mole of O2 (1 mole O2)

Procedure:

3 x 1 mole O2 ------ 879 kJ/mol

1 mole O2 ------ X

X = 293 kJ/mol

(notice that "-" means a release of heat)

Answer: 293 kJ/mol

In word equation, you need to write the name of each compound, reactants and products. In this case, it is:

Word:

sodium hydroxide + hydrochloric acid -> water + sodium chloride

The skeleton equation you must put the formulas of the compounds written in word equation.

Skeleton:

NaOH(aq) + HCl(aq) --> H2O(l) + NaCl(aq)

Answer:

Word:

sodium hydroxide + hydrochloric acid -> water + sodium chloride

Skeleton:

NaOH(aq) + HCl(aq) --> H2O(l) + NaCl(aq)

Answer:

a) 6.225 moles

b) 423.134grams

Explanations:

Given the balanced chemical equation as shown below:

[tex]4Al(s)+3O_2(g)\rightarrow2Al_2O_3[/tex]

a) Given the following parameters

Moles of aluminium = 8.3moles

According to stoichiometry, 4 moles of aluminium reacted with 3 moles of oxygen, the moles of oxygen are required to react with 8.3 moles of aluminum is expressed as:

[tex]\begin{gathered} mole\text{ of oxygen}=\frac{3moles\text{ of oxygen}}{4\cancel{moles\text{ of Al}}}\times8.3\cancel{moles\text{ of Al}} \\ mole\text{ of oxygen}=6.225moles \end{gathered}[/tex]

Hence the moles of oxygen required is 6.225moles

b) According to stoichiometry, 4 moles of Al produces 2 moles of aluminum oxide. The moles of aluminum oxide required will be:

[tex]\begin{gathered} mole\text{ of Al}_2O_3=\frac{2moles\text{ of Al}_2O_3}{4\cancel{moles\text{ of Al}}}\times8.3\cancel{moles\text{ of Al}} \\ mole\text{ of Al}_2O_3=4.15moles \end{gathered}[/tex]

Determine the mass of the product

[tex]\begin{gathered} Mass\text{ of Al}_2O_3=mole\times molar\text{ mass} \\ Mass\text{ of Al}_2O_3=4.15\times\frac{101.96g}{mol} \\ Mass\text{ of Al}_2O_3=423.134grams \end{gathered}[/tex]

Hence the mass of product that will be formed from 8.3 moles of aluminum is 423.134grams

In this question, we have to use the Calorimetry formula, which is the formula that perfectly correlates the change of temperature, mass and specific heat capacity of a specific substance, the formula is the following:

Q = mcΔT

We have:

m = 250g

c = 4.184 J/g°C

ΔT = 24°C

Now we add these values into the formula:

Q = 250 * 4.184 * 24

Q = 25104 J or 25.1 kJ will be the amount of heat

ANSWER

The element is carbon

Symbol of the element is C

The number of proton is 6

The number of neutron is 6

The atomic number is 6

EXPLANATION

The number of electrons = 6

The mass number of the element = 12

In a neutral atom, the number of electrons is always equal to the number of proton.

Since the number of electrons is 6, then the number of protons is 6

Recall, that mass number is the summation of number of proton and number of neutron

Mass number = number of proton + number of neutron

12 = 6 + number of neutron

Subtract 6 from both sides

12 - 6 = 6 - 6 + number of neutrons

Number of neutrons = 6

Therefore, the number of neutron is 6

The atomic number of the element is 6

The element is carbon

The question requires us to calculate the percent yield of a reaction, given its theoretical yield (3.76g) and actual yield (1.45g).

The percent yield of a reaction can be calculated by dividing the actual amount of product obtained - actual yield - by the amount of product that was expected - theoretical yield, and then multiplying this value by 100%:

[tex]\%yield=\frac{actual\text{ yield (g)}}{\text{theoretical yield (g)}}\times100\%[/tex]

Thus, considering the values provided by the question, we can calculate the percent yield of the reaction as it follows:

[tex]\%yield=\frac{1.45g}{3.76g}\times100\%=38.6\%[/tex]

(note that the values provided by the question present 3 significant figures, thus our answer must have the same amount of significant figures).

Therefore, the percent yield of the reaction is 38.6%.

STEP-BY-STEP EXPLANATION:

The electronic configuration of Calcium and Potassium is written below as

[tex]\begin{gathered} _{19}K_{}=1s^22s^22p^63s^23p^64s^1 \\ _{20}Ca=1s^22s^22p^63s^23p^64s^2 \end{gathered}[/tex]

Both calcium and potassium belong to period 4. Since the atomic radius is the distance between the nucleus and the electron moving around the outermost shell of the atom.

Potassium has more shielding than calcium. Hence, having more atomic radius than calcium

Potassium has an atomic number of 19 and calcium has an atomic number of 20. The nuclear charge of 20 0f calcium is shielded by 18 inner electrons while the nuclear charge of 19 potassium atoms is also shielded by 18 inner electrons. Therefore, the outer electrons of calcium are less shielded compared to the potassium atom. The outer electrons in calcium are 2 while Potassium is 1, so, it will be difficult to remove the electrons.

Recall that, both calcium and potassium belong to period 4 in the periodic table. Atomic radius increases down the group when we move from left to right and decreases across the period. As the atomic radius increases, the shielding effect also increases. Since they both have the same period, we can not judge their atomic radius by their group. Since the atomic radius increases from left to right and potassium is on the left to calcium, therefore, the atomic radius of potassium is greater than the atomic radius of calcium