Melissa burned her hand on the stove. Why did putting her hand in a bowl of cold water make the burn less severe?

Rank the following elements by effective nuclear charge, Zeff, for a valence electron. F LI Be B N

Stels [109]

Answer:

Rank in increasing order of effective nuclear charge:

Li < Be < B < N < F

Explanation:

This explains the meaning of effective nuclear charge, Zeff, how to determine it, and the calculations for a valence electron of each of the five given elements: F, Li, Be, B, and N.

1) Effective nuclear charge definitions

While the total positive charge of the atom nucleus (Z) is equal to the number of protons, the electrons farther away from the nucleus experience an effective nuclear charge (Zeff) less than the total nuclear charge, due to the fact that electrons in between the nucleus and the outer electrons partially cancel the atraction from the nucleus.

Such effect on on a valence electron is estimated as the atomic number less the number of electrons closer to the nucleus than the electron whose effective nuclear charge is being determined: Zeff = Z - S.

2) Z eff for a F valence electron:

F's atomic number: Z = 9
Total number of electrons: 9 (same numer of protons)
Period: 17 (search in the periodic table or do the electron configuration)
Number of valence electrons: 7 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 9 - 7 = 2
Zeff = Z - S = 9 - 2 = 7

3) Z eff for a Li valence eletron:

Li's atomic number: Z = 3
Total number of electrons: 3 (same number of protons)
Period: 1 (search on the periodic table or do the electron configuration)
Number of valence electrons: 1 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 3 - 1 = 2
Z eff = Z - S = 3 - 2 = 1.

4) Z eff for a Be valence eletron:

Be's atomic number: Z = 4
Total number of electrons: 4 (same number of protons)
Period: 2 (search on the periodic table or do the electron configuration)
Number of valence electrons: 2 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 4 - 2 = 2
Z eff = Z - S = 4 - 2 = 2

5) Z eff for a B valence eletron:

B's atomic number: Z = 5
Total number of electrons: 5 (same number of protons)
Period: 13 (search on the periodic table or do the electron configuration)
Number of valence electrons: 3 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 5 - 3 = 2
Z eff = Z - S = 5 - 2 = 3

6) Z eff for a N valence eletron:

N's atomic number: Z = 7
Total number of electrons: 7 (same number of protons)
Period: 15 (search on the periodic table or do the electron configuration)
Number of valence electrons: 5 (equal to the last digit of the period's number)
Number of electrons closer to the nucleus than a valence electron: S = 7 - 5 = 2
Z eff = Z - S = 7 - 2 = 5

7) Summary (order):

Atom Zeff for a valence electron

F 7

Li 1

Be 2

B 3

N 5

Conclusion: the order is Li < Be < B < N < F

6 0

3 years ago

In the name, iron(III) oxide, the (III) represents

Veronika [31]

<h2>In the name, iron(III) oxide, the (III) represents: D) the electrical charge of iron</h2><h2>Explanation:</h2>

To attain stability the chemical bond is formed .

Chemical bond

It is a kind of linkage that binds one atom with the other .

The atoms do so in order to attain stable noble gas configuration .

To form chemical bond they either:

Loose electrons : when atoms loose electrons they acquire positive charge which is equal to the number of electrons lost .

Gain electrons: After gaining electrons they acquire negative charge which is equal to the number of electrons gained by an atom.

share electrons : With sharing no charges are develop .

In the above asked question when iron combines with oxygen it forms iron oxide : where iron looses 3 electrons and oxygen gains 2 electrons .That is the reason ,III here represents the electrical charge of iron

7 0

3 years ago

How many joules of energy is required to bring a five-pound (1 pound = 454 g) bag

sweet-ann [11.9K]

The answer is 4567 grams of ice in the five pound bag to specific heat is the -20 degrees! Hope I helped! :)

5 0

3 years ago

Two liters of hydrogen gas are stored at a

Tju [1.3M]

Answer:

the volume will expand

Explanation:

gas under pressure contracts, and expands with a lesser pressure

6 0

3 years ago

What is the term used to describe why urban areas are warmer than surrounding rural areas?

4vir4ik [10]

Answer:

urban heat island

Explanation:

occurs when a city experiences much warmer temperatures than nearby rural areas.

Mark me brainliest.

5 0

2 years ago