If two forces are heading in the same direction, we _____

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

7.02 x 10^23 molecules of X2, a ssubstance consisting of diatomic molecules, has a mass of 296 grams. Determine the atomic weigh

Fiesta28 [93]

Answer:

d. 127 g/mol.

Explanation:

Hello!

In this case, since we have the amount of molecules of this this compound, we are able to compute the moles out there by using the Avogadro's number:

$mol=7.02x10^{23}molec*\frac{1mol}{6.022x10^{23}molec}=1.17mol$

Which correspond to the moles of X2. Then, by using the mass we are able to compute the molar mass of X2:

$MM=\frac{296g}{1.17mol}\\\\MM=254g/mol$

It means that the atomic mass of X halves the molar mass of X2, which is then d. 127 g/mol.

Best regards!

4 0

2 years ago

A student practicing for the outdoor track team begins to sweat. To what stimulus is the body responding?

cricket20 [7]

Answer:

A student practicing for the outdoor track team begins to sweat. To what stimulus is the body responding?

Explanation:

3 0

2 years ago

Read 2 more answers

Calcium reacts with Hydrochloric acid to produce Calcium chloride and

hammer [34]

Answer:

Mass = 2.77 g

Explanation:

Given data:

Mass of HCl = 2 g

Mass of CaCl₂ produced = ?

Solution:

Chemical equation:

2HCl + Ca → CaCl₂ + H₂

Number of moles of HCl:

Number of moles = mass / molar mass

Number of moles = 2 g/ 36.5 g/mol

Number of moles = 0.05 mol

now we will compare the moles of HCl with CaCl₂.

HCl : CaCl₂

2 : 1

0.05 : 1/2×0.05 = 0.025 mol

Mass of CaCl₂:

Mass = number of moles × molar mass

Mass = 0.025 mol × 110.98 g/mol

Mass = 2.77 g

8 0

3 years ago

What did Mendel do that made his predictions so accurate

Hoochie [10]

He worked with large numbers of plants.

8 0

3 years ago

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If two forces are heading in the same direction, we ______ them to calculate net force.