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3 years ago

Select the set of quantum numbers that represents each electron in a ground‑state be atom.

Chemistry

1 answer:

lukranit [14]3 years ago

3 0

Answer:

There are four electronsin a beryllium atom. The four set of quantum numbers for the ground-state beryllium atom are:

n = 1, ℓ = 0, mℓ = 0, ms = +1/2

n = 1, ℓ = 0, and mℓ = , ms = -1/2

n = 2, ℓ = 0, mℓ = 0, ms = +1/2

n = 2, ℓ = 0, and mℓ = , ms = -1/2

Explanation:

Be is the chemical symbol for beryllium.

The atomic number of beryllium is 4.

Hence, beryllium atoms have 4 protons and 4 electrons.

The electron configuration for the ground-state Be atom, is:

1s² 2s²

So, you have to find the sets of quantum numbers for the two 1s and the two 2 s electrons.

For the two 1s electrons:

Principal quantun number, n.

The principal quantum number, n, is the main energy level and is indicated by the number in front of the letter (kind of orbital).

So, for the two 1s electrons, n = 1

Orbital Angular Momentum Quantum Number, ℓ

The angular moment quantum number, ℓ, is the shape of the orbital.

The possible numbers for ℓ are from 0 to n- 1. Orbital s means ℓ = 0.

Magnetic Quantum Number, mℓ

The magnetic quantum number, mℓ, represents the space orientation of the orbital.

The possible numbers for mℓ are from - ℓ to + ℓ. Hence, for the two `s electrons mℓ is 0.

So far you have: n = 1, ℓ = 0, and mℓ = 0.

Spin quantum number, s or ms

The spin quantum number, related to the rotation of the electron, may be only +1/2 or -1/2.

So, now you have the two sets for these two electrons:

n = 1, ℓ = 0, mℓ = 0, ms = +1/2

n = 1, ℓ = 0, and mℓ = , ms = -1/2

For the two 2s electrons:

n = 2

ℓ = 0 (because the orbital is 2)

mℓ = 0 (because ℓ = 0)

ms = +1/2 or -1/2.

So, the two sets for the two s electrons are:

n = 2, ℓ = 0, mℓ = 0, ms = +1/2

n = 2, ℓ = 0, and mℓ = , ms = -1/2

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sergiy2304 [10]

Answer:

I. dissolving more solute in an unsaturated solution

Explanation:

A saturated solution is the solution which contains maximum concentration of solute dissolved in solvent.

However, if the solution is being provided with energy (heating) , it will dissolve more heat and the solution that cannot even dissolve more solute after heating is super saturated solution.

Both saturated and supersaturated solutions have maximum of their capacity to dissolve the solute and hence further energy requires energy and these processes are non-spontaneous.

An unsaturated solution can dissolve more solute easily and thus is a spontaneous process.

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4 years ago

Consider the following balanced equation for the following reaction:

balandron [24]

Answer: The amount of carbon dioxide formed in the reaction is 47.48 grams

Explanation:

For the given chemical equation:

$15O_2(g)+2C_6H_5COOH(aq.)\rightarrow 14CO_2(g)+6H_2O(l)$

To calculate the actual yield of carbon dioxide, we use the equation:

$\%\text{ yield}=\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100$

Percentage yield of carbon dioxide = 83 %

Theoretical yield of carbon dioxide = 1.30 moles

Putting values in above equation, we get:

$83=\frac{\text{Actual yield of carbon dioxide}}{1.30moles}\times 100\\\\\text{Actual yield of carbon dioxide}=\frac{1.30\times 83}{100}=1.079moles$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of carbon dioxide = 44 g/mol

Moles of carbon dioxide = 1.079 moles

Putting values in above equation, we get:

$1.079mol=\frac{\text{Mass of carbon dioxide}}{44g/mol}\\\\\text{Mass of carbon dioxide}=(1.079mol\times 44g/mol)=47.48g$

Hence, the amount of carbon dioxide formed in the reaction is 47.48 grams

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4 years ago

When lithium nitride, Li 3 N ( s ) , is treated with water, H 2 O ( l ) , ammonia, NH 3 ( g ) , is produced. Predict the formula

allochka39001 [22]

Answer : The formula of the gas produced is, $PH_3$ (phosphine gas)

Explanation :

According to the question, when sodium phosphide is treated with water then it react to give phosphine gas and sodium hydroxide.

The balanced chemical reaction will be:

$Na_3P(aq)+3H_2O(l)\rightarrow PH_3(g)+3NaOH(aq)$

By Stoichiometry of the reaction we can say that:

1 mole of sodium phosphide reacts with 3 moles of water to give 1 mole of phosphine gas and 3 moles of sodium hydroxide.

Thus, the formula of the gas produced is, $PH_3$ (phosphine gas)

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3 years ago

When 0.300 g of a diprotic acid was titrated with 0.100 M LiOH, 40.0 mL of the LiOH solution was needed to reach the second equi

Iteru [2.4K]

Answer:

H₂C₄H₄O₆

Explanation:

The clue of this question is to find the molar mass of the diprotic acid and compare witht the molars masses of the choices' acid to identify the formula of the diprotic acid.

The procedure is:

Find the number of moles of the base: LiOH
Use stoichionetry to infere the number of moles of the acid.
Use the formula molar mass = mass in grams / number of moles, to find the molar mass of the diprotic acid.
Compare and conclude.

Solution:

1. Number of moles of the base, LiOH:

M = n / V in liter ⇒ n = M × V = 0.100 M × 40.0 ml × 1 liter / 1,000 ml = 0.004 mol LiOH.

2. Stoichiometry:

Since this a neutralization reaction of a diprotic acid with a mono hydroxide base (LiOH), the mole ratio at the second equivalence point is: 2 mol of base / 1 mole of acid; because each mole of LiOH releases 1 mol of OH⁻, while each mole of diprotic acid releases 2 mol of H⁺.

Hence, 0.004 mol LiOH × 1 mol acid / 2 mol LiOH = 0.002 mol acid.

3. Molar mass of the acid:

molar mass = mass in grams / number of moles = 0.300 g / 0.002 mol = 150. g/mol

4. Molar mass of the possible diprotic acids:

a. H₂Se: 2×1.008 g/mol + 78.96 g/mol = 80.976 g/mol

b. H₂Te: 2×1.008 g/mol + 127.6 g/mol = 129.616 g/mol

c. H₂C₂O₄ ≈ 2×1.008 g/mol + 2×12.011 g/mol + 4×15.999 g/mol ≈ 90.034 g/mol

d. H₂C₄H₄O₆ = 6×1.008 g/mol + 4×12.011 g/mol + 6×15.999 g/mol = 150.086 g/mol ≈ 150 g/mol.

Conclusion: since the molar mass of H₂C₄H₄O₆ acid is 150 g/mol, you conclude that is the diprotic acid whose 0.300 g were titrated with 40.0 ml of 0.100 M LiOH solution.

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3 years ago

What does the line with “alternating spikes and semicircles” mean?

Usimov [2.4K]

Answer:

The line with spikes and semicircles is a stationary front, it brings days of steady rain.

Explanation:

L means Low pressure, it brings stormy weather with strong winds.

H means High pressure, it brings fair weather and light winds.

The line with spikes is a cold weather front, it brings thunderstorms and colder

temperatures.

The line with spikes and semicircles is a stationary front, it brings days of steady rain.

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3 years ago