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3 years ago

Given the following electronic configurations, identify how many valence electrons each atom has.

Chemistry

2 answers:

ololo11 [35]3 years ago

4 0

Answer : Valence electrons in atom A = 1, B = 6 and C = 2.

Explanation :

Valence electrons means the outermost electrons are the ones which involved in bonding. Electrons are arranged in energy levels or shells.

Valence electrons are found in the highest energy orbitals of an element.

The electronic configuration of (Na) is $1s^22s^22p^63s^1$ . The highest energy orbital is 3s orbital which contains 1 electron. So,

The number of valence electrons in (Na) = A = 1

Similarly,

The electronic configuration of (O) is $1s^22s^22p^4$ . The highest energy orbital are 2s and 2p orbitals which contains (2 + 4) = 6 electrons. So,

The number of valence electrons in (O) = B = 6

The electronic configuration of (Fe) is $1s^22s^22p^63s^23p^64s^23d^6$ . The highest energy orbital is 4s orbital which contains 2 electrons. So,

The number of valence electrons in (Fe) = C = 2

Papessa [141]3 years ago

3 0

correct answer would be 1,6, and 8 so a=1, 6, c=8.

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A gas under a pressure of 74 mmHg and at a temperature of 75°C occupies a 500.0-L container. How many moles of gas are in the co

Leona [35]

Answer : The number of moles of gas present in container are 1.697 mole.

Explanation :

Using ideal gas equation,

$PV=nRT$

where,

P = pressure of gas = 74 mmHg = 0.097 atm

conversion used : (1 atm = 760 mmHg)

V = volume of gas = 500.0 L

T = temperature of gas = $75^oC=75+273=348K$

n = number of moles of gas = ?

R = gas constant = 0.0821 L.atm/mole.K

Now put all the given values in the ideal gas equation, we get the number of moles of gas in the container.

$(0.097atm)\times (500.0L)=n\times (0.0821L.atm/mole.K)\times (348K)$

$n=1.697mole$

Therefore, the number of moles of gas present in container are 1.697 mole.

4 0

3 years ago

max2010maxim [7]

Answer: the mass of the object

Explanation: To find density, the equation d= m/v is needed where m= mass and v= volume

7 0

2 years ago

How many grams of NaOH are<br> needed to make 400. mL of<br> 1.50 M solution?

juin [17]

Answer:

24g of NaOH are required

Explanation:

Molarity, M, is an unit of concentration widely used in chemistry defined as the ratio between moles of solute (In this case, NaOH), and volume of solution in liters.

We can find the moles of NaOH and its mass with the volume and desired concentration as follows:

<em>Moles NaOH:</em>

400.0mL = 0.400L * (1.50mol / L) = 0.600 moles NaOH

<em>Mass NaOH -Molar mass: 40.0g/mol-:</em>

0.600 moles * (40.0g / mol) =

<h3>24g of NaOH are required</h3>

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3 years ago

Which statement below best describes mutations?

Studentka2010 [4]

Answer:

C. Mutations are a change in DNA or a chromosome and can be helpful, harmful or may have no affect.

Explanation:

Mutations are spontaneous random changes that occurs in the genetic make up of an organisms. Mutations are rare and their rate of occurrence is random.
Mutations may occur on the gene level known as gene mutations or at chromosome levels called chromosomal mutations.
Mutations may be beneficial, harmful or have no effect on a given organisms. Harmful mutations cause disorders that may lead to abnormality or death of an organisms. Beneficial mutations improve an organisms adaptability to the environment.

8 0

3 years ago

can someone please explain me electronic arrangement of different elements please tomorrow is my paper i neEd help ASAP !!!!!!!

NNADVOKAT [17]

Answer:

This list of electron configurations of elements contains all the elements in increasing order of atomic number.

To save room, the configurations are in noble gas shorthand. This means part of the electron configuration has been replaced with the element symbol of the noble gas symbol. Look up the electronic configuration of that noble gas and include that value before the rest of the configuration.

Explanation:

hope this help

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2 years ago