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dexar [7]
3 years ago
14

How many of the following elements have 2 unpaired electrons in the ground state? C Te Hf Si

Chemistry
1 answer:
AleksAgata [21]3 years ago
5 0

Answer:

  • Option C) 3.

  • C, Te, and Si have two unpaired electrons in the ground state.

Explanation:

You must draw the electron configuration.

<u><em>C (carbon)</em></u>

  • Atomic number (Z): 12
  • Number of electrons: 12
  • Electron configuration of ground state, following Aufbau rules (filling orbitals in order of increasing energy):

        1s² 2s² 2p²

  • Electron pairing following Hund's rules (fill different orbitals of same energy, with same spin, before adding a second electron, with opposite spin, to an orgital).

        1s² 2s² 2px↑ 2py↑

  • As you see, these configuration shows two unpaired electrons (same spin) in the ground state.

<u><em>Te (tellurium)</em></u>

  • Z = 52
  • Number of electrons: 52
  • Aufbau's rule and short notation: [Kr] 5s² 4d¹⁰ 5p⁴
  • Hund's rule:  [Kr] 5s² 4d¹⁰ 5px↑↓ 5py↑ 5pz↑
  • This configuration shows two unpaired elecctrons (same spin).

<u><em>Hf (hafnium)</em></u>

<u><em></em></u>

  • Z = 72
  • Number of electrons: 72
  • Aufbau's rule and short notation: [Xe] 4f¹⁴ 5d²6s²
  • This configuration shows that there are not unpaired electrons (the las orbital 6s is complete with 2 electrons)

<u><em>Si (silicon)</em></u>

<u><em></em></u>

  • Z = 14
  • Number of electrons: 14
  • Aufbau's rule and short notation: [Ne] 3s² 3p²
  • Hund's rule: [Ne] 3s² 3px↑ 3py↑
  • This configuration shows two unpaired electrons.

Conclusion: C, Te and Si, have two unpaired electrons (same spin) in the ground state.

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Please show all work for full credit.
koban [17]

Answer:

No, it is not sufficient

Please find the workings below

Explanation:

Using E = hf

Where;

E = energy of a photon (J)

h = Planck's constant (6.626 × 10^-34 J/s)

f = frequency

However, λ = v/f

f = v/λ

Where; λ = wavelength of light = 325nm = 325 × 10^-9m

v = speed of light (3 × 10^8 m/s)

Hence, E = hv/λ

E = 6.626 × 10^-34 × 3 × 10^8 ÷ 325 × 10^-9

E = 19.878 × 10^-26 ÷ 325 × 10^-9

E = 19.878/325 × 10^ (-26+9)

E = 0.061 × 10^-17

E = 6.1 × 10^-19J

Next, we work out the energy required to dissociate 1 mole of N=N. Since the bond energy is 418 kJ/mol.

E = 418 × 10³ ÷ 6.022 × 10^23

E = 69.412 × 10^(3-23)

E = 69.412 × 10^-20

E = 6.9412 × 10^-19J

6.9412 × 10^-19J is required to break one mole of N=N bond.

Based on the workings above, the photon, which has an energy of 6.1 × 10^-19J is not sufficient to break a N=N bond that has an energy of 6.9412 × 10^-19J

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3 years ago
Ian uses litmus paper to determine whether five unknown solutions are acids or bases. The litmus paper turns red when the pH is
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Answer: b

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3 years ago
Electron A falls from energy level X to energy level Y and releases blue light. Electron B falls from energy level Y to energy l
MrMuchimi

Answer: Transition from X to Y will have greater energy difference.

Explanation: For studying the energy difference, we require Planck's equation.

                                E=\frac{hc}{\lambda}

where, h = Planck's Constant

c = Speed of light

E = Energy

\lambda = Wavelength of particle

From the equation, it is visible that the energy and wavelength follow inverse relation which means that with low wavelength value, energy will be the highest and vice-versa.

As electron A falls from X-energy level to Y-energy level, it releases blue light which has low wavelength value (around 470 nm) which means that it has high energy.

Similarly, Electron B releases red light when it falls from Y-energy level to Z-energy level, which has high wavelength value (around 700 nm), giving it a low energy value.

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5 0
3 years ago
A pipe leaks water at a rate of 1.24 mL/s. What is the rate of the water leak in L/hr?
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Answer:

b)4.46 L/hr

Explanation:

To solve this question we need to convert the mL to liters (Using the conversion of 1000mL = 1L) and convert the time from seconds to hours (3600s = 1hr)

<em>mL to L:</em>

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<em>seconds to hours:</em>

0.00124L/s * (3600s / 1hr) = 4.46L/hr

Right answer is:

<h3>b)4.46 L/hr </h3>

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