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3 years ago

The value of Zeff for a valence electron in an atom of silicon is?

1 answer:

6 0

Zeff is the effective nuclear charge wherein, Z resembles the number of protons in the nucleus while S corresponds to the number of non-valence electrons.

Zeff = Z - S

Silicon has 14 protons; its electron configuration is [Ne] 3s2 3p2. Its non-valence electrons is in the n = 1 and n =2 shells. There are 2 electrons in n = 1 and 8 in n = 2, so there are a total of 10 non-valence electron.

Zeff= 14−10= 4

So, the answer is 4.

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Name the following alkyne. Please help me <3

Alexandra [31]

Answer:

D. 7-methyl-3-octyne

Explanation:

1) Identify the parent chain and name it like an alkane.

• The longest chain of carbons, which consists of the functional group (which is the alkyne group in this case: C≡C).

• There are 8 carbons in the longest chain, so it is called an octane.

2) Now, identify the location of the functional group.

• The location number of the functional group should be as low as possible. Thus although we could count from the right, we start counting from the left since the functional group is closer to the left. From the left, the functional group would be at carbon 8 while from the left, it is on carbon 3.

• Replace 'ane' with 'yne' in octane for the alkyne group.

• This would give us 3-octyne.

3) Lastly, add in the name of the branch.

• Here we have one branch, -CH₃. This is read as methyl.

• Identify the location number of the branch by counting the number of carbons in the same direction as when we counted the location number of the functional group. The methyl branch has a location number of 7.

• Adding the name of the branch before the parent chain, we would arrive at 7-methyl-3-octyne as the IUPAC name of the alkyne.

Further Explanation:

A) This option is incorrect as there are only 8 carbons in the parent chain. Although there are 9 carbons in total, the 9th carbon is taken care of in '7-methyl'.

B) Location number of the functional group should be as low as possible, so start counting the number of carbons from the left!

C) Since the functional group is an alkyne, the word 'octane' should be 'octyne' instead.

8 0

3 years ago

Consider an atom having four distinct energy levels. If an electron is able to make transitions between any two levels, how many

Kryger [21]

Energy levels are the electron shells where electrons are found at a fixed distance from the nucleus of the atom. The atom could emit 6 different wavelengths.

<h3>What is wavelength?</h3>

A wavelength is a distance between the adjacent crests in wave signals propagated in a system. Wavelength $(\rm \lambda )$ is in inverse relation to the frequency of the wave.

When an electron jumps from energy level 1 to 2, 1 to 3, and 1 to 4 one wavelength each is present. Hence, making the total wavelength to be 3, in transition from the first energy level.

Similarly, from energy levels, 2 to 3 and 2 to 4, a total of 2 wavelengths, and from energy levels 3 to 4 one wavelength is produced.

So the total different wavelengths of the radiation that can be emitted will be 3 + 2 + 1 = 6.

Therefore, 6 different wavelengths of radiation will be emitted by the atom.

Learn more about wavelengths here:

brainly.com/question/21419520

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7 0

2 years ago

When silver nitrate reacts with copper, copper(II) nitrate and silver are produced. The balanced equation for this reaction is:

posledela

The question is incomplete, here is the complete question:

When silver nitrate reacts with copper, copper(II) nitrate and silver are produced. The balanced equation for this reaction is:

$2AgNO_3+Cu\rightarrow Cu(NO_3)_2+2Ag$

Suppose 6 moles of silver nitrate react. The reaction consumes___ moles of copper. The reaction produces __ moles of copper(II) nitrate and __ moles of silver.

Answer: The amount of copper metal reacted is 3 moles, amount of copper (II) nitrate produced is 3 moles and amount of silver metal produced is 6 moles.

Explanation:

We are given:

Moles of silver nitrate = 6 moles

For the given chemical reaction:

$2AgNO_3+Cu\rightarrow Cu(NO_3)_2+2Ag$

For copper metal:

By Stoichiometry of the reaction:

2 moles of silver nitrate reacts with 1 mole of copper metal

So, 6 moles of silver nitrate will react with = $\frac{1}{2}\times 6=3mol$ of copper metal

Moles of copper reacted = 3 moles

For copper(II) nitrate:

By Stoichiometry of the reaction:

2 moles of silver nitrate produces 1 mole of copper(II) nitrate

So, 6 moles of silver nitrate will produce = $\frac{1}{2}\times 6=3mol$ of copper(II) nitrate

Moles of copper(II) nitrate produced = 3 moles

For silver metal:

By Stoichiometry of the reaction:

2 moles of silver nitrate produces 2 moles of silver metal

So, 6 moles of silver nitrate will produce = $\frac{2}{2}\times 6=6mol$ of silver metal

Moles of silver metal produced = 3 moles

Hence, the amount of copper metal reacted is 3 moles, amount of copper (II) nitrate produced is 3 moles and amount of silver metal produced is 6 moles.

6 0

3 years ago

What forms the structure called a coral reef

lina2011 [118]

When the little fish die they sink to the bottom, and after time the skeletons build up on top of each other.

7 0

3 years ago

Read 2 more answers

Since helium is lighter than air, it is difficult to measure the mass of a sample, so to find out the mass of helium in a birthd

d1i1m1o1n [39]

Answer:

0.7457 g is the mass of the helium gas.

Explanation:

Given:

Pressure = 3.04 atm

Temperature = 25.0 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T₁ = (25.0 + 273.15) K = 298.15 K

Volume = 1.50 L

Using ideal gas equation as:

$PV=nRT$

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

3.04 atm × 1.50 L = n × 0.0821 L.atm/K.mol × 298.15 K

⇒n = 0.1863 moles

Molar mass of helium = 4.0026 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$0.1863\ mole= \frac{Mass}{4.0026\ g/mol}$

$Mass_{He}= 0.7457\ g$

0.7457 g is the mass of the helium gas.

6 0

3 years ago