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3 years ago

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.

C (carbon)

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.

Te (tellurium)

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).

Hf (hafnium)

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)

Si (silicon)

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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What reaction might we use to synthesize nickel sulfate,niso4? Write equations for acid base neutralization. Include states in y

il63 [147K]

Answer:

Here's what I get

Explanation:

1. Nickel sulfate

base + acid ⟶ salt + water

NiSO₄ is a salt of the base Ni(OH)₂ and the acid sulfuric acid.

Hydroxides of transition metals are insoluble; most sulfates are soluble.

$\underbrace{\hbox{Ni(OH)$_{2}$(s)}}_{\hbox{base}} + \underbrace{\hbox{H$_{2}$SO$_{4}$(aq)}}_{\hbox{acid}} \longrightarrow \, \underbrace{\hbox{NiSO$_{4}$(aq)}}_{\hbox{salt}} + \underbrace{\hbox{2H$_{2}$O(l)}}_{\hbox{water}}$

2. Carbonate + acid

Most carbonates are insoluble.

They react with acids to form carbonic acid (H₂CO₃), which decomposes into water and carbon dioxide.

$\rm NiCO_{3}(s) + H_{2}SO_{4}(aq) \longrightarrow \, NiSO_{4}(aq) + H_{2}O(l) + CO_{2}(g)$

5 0

3 years ago

What part of the sun do we see from earth?

NISA [10]

Answer:

photosphere

Explanation:

photosphere

There are 3 main layers of the Sun that we can see. They are the photosphere, the chromosphere and the corona. Together they make up the "atmosphere" of the Sun. The part of the Sun that glows (and that we see with the naked eye) is called the photosphere

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3 years ago

Read 2 more answers

What is the volume of 2 mol of chlorine gas at STP? 2.0 L 11.2 L 22.4 L 44.8 L

nirvana33 [79]

Answer:

44.8 L

Explanation:

Using the ideal gas law equation:

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

At Standard temperature and pressure (STP);

P = 1 atm

T = 273K

Hence, when n = 2moles, the volume of the gas is:

Using PV = nRT

1 × V = 2 × 0.0821 × 273

V = 44.83

V = 44.8 L

7 0

2 years ago

The question is in the picture below

Rus_ich [418]

Answer:

$\Delta\text{H}_1+2\Delta\text{H}_2-\Delta\text{H}_3$

Explanation:

Hess's Law of Constant Heat Summation states that if a chemical equation can be written as the sum of several other chemical equations, the enthalpy change of the first chemical equation is equal to the sum of the enthalpy changes of the other chemical equations. Thus, the reaction that involves the conversion of reactant A to B, for example, has the same enthalpy change even if you convert A to C, before converting it to B. Regardless of how many steps it takes for the reactant to be converted to the product, the enthalpy change of the overall reaction is constant.

With Hess's Law in mind, let's see how A can be converted to 2C +E.

$\bf{\text{A} \rightarrow 2\text{B}}$ (Δ $\text{H}_1$ ) -----(1)

Since we have 2B, multiply the whole of II. by 2:

$\bf{2\text{B} \rightarrow 2\text{C} +2\text{D}}$ (2Δ $\text{H}_2$ ) -----(2)

This step converts all the B intermediates to 2C +2D. This means that the overall reaction at this stage is $\text{A} \rightarrow 2\text{C} +2\text{D}$ .

Reversing III. gives us a negative enthalpy change as such:

$\bf{2\text{D} \rightarrow \text{E}}$ (-Δ $\text{H}_3$ ) -----(3)

This step converts all the D intermediates formed from step (2) to E. This results in the overall equation of $\text{A} \rightarrow 2\text{C} +\text{E}$ , which is also the equation of interest.

Adding all three together:

$\text{A} \rightarrow 2\text{C}+\text{E}$ ( $\bf{\Delta\text{H}_1+2\Delta\text{H}_2-\Delta\text{H}_3 }$ )

Thus, the first option is the correct answer.

Supplementary:

To learn more about Hess's Law, do check out: brainly.com/question/26491956

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1 year ago

A chemist wants to examine specific chemical reactions and isolate certain products using a controlled experiment. How would the

professor190 [17]

Answer:

in a laboratory

Explanation:

A controlled experiment refers to the one where everything is an experiment except a single variable is held constant. A collection of information is typically taken as a control group, which is generally the ordinary state, and another group is analyzed( such as chemical reaction as per the question) in which all conditions are similar to the control group except for the variable under examination. The main benefit of a controlled experiment is that confusion over the accuracy of the results can be eliminated more easily.

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3 years ago