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Mama L [17]
3 years ago
14

Which of the following quantum number combinations is not allowed in a ground-state atom? (7, 4, -2, -½) (3, 0, 0, +½) (2, 1, 1,

-½) (3, 2, 3, +½)
Chemistry
1 answer:
rusak2 [61]3 years ago
7 0
The last combination (3,2,3,+1/2) is not allowed.

The quantum numbers are (n, l, ml, s)

l, the second quantum number, may take values from 0 to n - 1; so:

n = 3 => l may be 0, 1, or 2 => the first and second quantum numbers are a valid combination.

The third quantum number, ml goes from - l to +l, so, given that l is lower than 3, ml cannot be 3. That is why this is not a valid combination.
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Which of the following ions has the smallest ionic radius?
maria [59]

Answer:

The C4+ ion has the smallest ionic radius

Explanation:

In the periodic table, the size of an atom increases on going downwards in a group.

On the other hand, in a period, size decreases on going from left to right

The size of cation is smaller than its parent atom.

Lithium-ion (Li+) is the most left so it has the biggest radius.

More to the right ( this means a smaller ionic radius) , we have Berylium-ion (Be2+).

More to the right, so smaller than Be2+, we have B3+

The ion the most to the right, we have C4+

The C4+ ion has the smallest ionic radius

Li+ > Be2+ > Be3+ > C4+

7 0
3 years ago
Read 2 more answers
The solubility of oxygen gas in water at 40 ∘c is 1.0 mmol/l of solution. What is this concentration in units of mole fraction?
juin [17]

The formula for mole fraction is:

mole fraction of solute = \frac{number of moles of solute}{total number of moles of solution}    -(1)

The solubility of oxygen gas = 1.0 mmol/L  (given)

1.0 mmol/L means 1.0 mmol are present in 1 L.

Converting mmol to mol:

1.00 mmol\times \frac{1 mol}{1000 mmol} = 0.001 mol

So, moles of oxygen = 0.001 mol

For moles of water:

1 L of water = 1000 mL of water

Since, the density of water is 1.0 g/mL.

Density = \frac{mass}{volume}

Mass = 1.0 g/ml\times 1000 mL = 1000 g

So, the mass of water is 1000 g.

Molar mass of water = 18 g/mol.

Number of moles of water = \frac{1000 g}{18 g/mol} = 55.55 mol

Substituting the values in formula (1):

mole fraction = \frac{0.001}{55.55+0.001}

mole fraction = 1.8\times 10^{-5}

Hence, the mole fraction is 1.8\times 10^{-5}.

7 0
3 years ago
In your own words, describe how the energy of a pendulum is changed as it moves through one cycle of its motion. Pls help online
ruslelena [56]

In a perfect world without air resistance, the top of the swing would have the most potential energy, but the least amount of kinetic energy. As the pendulum falls down, it gains more kinetic energy as it travels faster due to gravitational acceleration but loses more potential energy as it loses height. The total amount of energy in the system (the sum of kinetic and potential energy) stays the same.

3 0
4 years ago
A buffer solution is prepared by placing 5.86 grams of sodium nitrite and 32.6 mL of a 4.90 M nitrous acid solution into a 500.0
N76 [4]

This question is incomplete, the complete question is;

A buffer solution is prepared by placing 5.86 grams of sodium nitrite and 32.6 mL of a 4.90 M nitrous acid solution into a 500.0 mL volumetric flask and diluting to the calibration mark. If 10.97 mL of a 1.63 M solution of potassium hydroxide is added to the buffer, what is the final pH? The Ka for nitrous acid = 4.6 × 10⁻⁴.

Answer:

the final pH is 3.187

Explanation:

Given the data in the question;

Initial moles of HNO2 = 32.6/1000 × 4.90 = 0.15974 mol

Initial moles of NO2- = mass/molar mass = 5.86/68.995 =  0.0849336 mol

Moles of KOH added = 10.97/1000 × 1.63  = 0.0178811 mol

so

HN02 + KOH → NO2- + H2O

moles of HNO2 = 0.15974 - 0.0178811 = 0.1418589 mol

Moles of NO2- = 0.0849336 + 0.0178811  =  0.1028147 mol

Now,

pH = pka + log( [NO2-]/[HNO2])

pH = -log ka + log( moles of NO2- / moles of HNO2 )

we substitute

pH = -log( 4.6 × 10⁻⁴ ) + log( 0.1028147  / 0.1418589  )

pH = -log( 4.6 × 10⁻⁴ ) + log( 0.724767 )

pH =  3.337242 + (-0.1398 )

pH = 3.187

Therefore, the final pH is 3.187

8 0
3 years ago
Ytu perform an electrolysis reaction using FeCl, iron (1) chloride. Which of the following will happen?
FrozenT [24]

Answer:

The answer is "Option B"

Explanation:

when we react with FeCl, iron, and chloride to both the electrolysis. So, iron is charged positive ion, as well as passes to the negative, is cathode electrode. But there is a decrease in the cathode.

The equation can be defined as follows:

FeCl_2 \longrightarrowFe + Cl_2

In the above equation, when the iron chloride electrolysis solution, it will give the iron(II) and the chlorine. This process happens when the hydrogen chloride solution at a temperature of about 90 ° C.

5 0
4 years ago
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