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Rasek [7]
4 years ago
13

What is the neutral atom that has its first two energy levels filled, has 8 electrons in its third energy level, and has no othe

r electrons? Enter the name of the element, not the abbreviation.
Chemistry
2 answers:
Ganezh [65]4 years ago
8 0
Argon

Ar 1s²2s²2p⁶3s²3p⁶
zubka84 [21]4 years ago
8 0

Answer:

Argon

Explanation:

The arrangement of electrons in an atom is governed by the Aufbau principle according to which electrons are added to atomic orbitals such that the lowest energy orbitals get occupied first before the higher energy orbitals. The arrangement of energy levels in increasing energy order is:

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p......

's' , 'p', 'd' orbitals can accommodate a maximum of 2,6 and 10 electrons respectively.

From the given information:

First energy level corresponds to n = 1, and is fully filled i.e. 1s²

Second energy level corresponds to n = 2, and is fully filled i.e. 2s²2p⁶

Third energy level corresponds to n = 3 and it has 8 electrons i.e. 3s²3p⁶

The neutral atom has a total of 18 electrons with an electronic configuration of:

1s²2s²2p⁶3s²3p⁶

Based on the periodic table the atom is with atomic number = 18 is argon (Ar)

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Which best explains why on ization energy tends to decrease from the top to the bottom of a group
Ostrovityanka [42]

Answer:

ionization energy is the amount of energy it takes to remove an atoms most loosely bound electron. going from the top of a group to the bottom, ionization energy decreases, as it is getting easier and easier to remove the outermost electron. As you move down a group, you add principle energy levels, which causes shielding. this means that there is decreased communication between the outermost electron and the nucleus, making it easier to remove the outer electron.

4 0
3 years ago
How many molecules would there be in 10.5 L of carbon dioxide at 40.0 C and 252 kPa
kakasveta [241]

Answer:

6.14×10²³ molecules

Explanation:

Data obtained from the question include:

Volume (V) = 10.5L

Temperature (T) = 40°C

Pressure (P) = 252 kPa

Next, we shall determine the number of mole of CO2 present.

This can be obtained by using the ideal gas equation:

PV = nRT

Volume (V) = 10.5L

Temperature (T) = 40°C = 40°C + 273 = 313K

Pressure (P) = 252 kPa

Gas constant (R) = 8.31 KPa.L/Kmol

Number of mole (n) =.?

PV = nRT

252 x 10.5 = n x 8.31 x 313

Divide both side by 8.31 x 313

n = (252 x 10.5) /(8.31 x 313)

n = 1.02 mole

Therefore, 1.02 mol of CO2 is present.

Now, we can obtain the number of molecules of CO2 present as follow:

From Avogadro's hypothesis, 1 mole of any substance contains 6.02×10²³ molecules.

This means that 1 mole of CO2 also contains 6.02×10²³ molecules.

Now, if 1 mole of CO2 contains 6.02×10²³ molecules,

Then 1.02 mole will contain = 1.02 x 6.02×10²³ = 6.14×10²³ molecules.

Therefore, 6.14×10²³ molecules of CO2 is present.

8 0
4 years ago
How many atoms are in 9.008 mol of Carbon? 0.7500 atoms 1.332 atoms 5.423 x 10^24 atoms 1.496 x 10^ -23 atoms
Zanzabum

 The number  of atoms that are  in 9.008   moles of carbon is

5.423 x 10^24 atoms


<u><em>calculation</em></u>

The  number of atoms is calculated using the Avogadro's   constant

That is   According to  Avogadro's   1  moles  = 6.02 x 10^23  atoms

                                                         9.008  moles= ? atoms

by cross multiplication

= [(9.008  moles x 6.02 x 10^23 atoms)  / 1  mole] = 5.423 x10^24 atoms

8 0
3 years ago
The actions described in the passage are best understood in the context of which of the following?
soldi70 [24.7K]
C
I have had this question on a test before!! Hope this helps
6 0
4 years ago
The molarity of an aqueous solution of NaCl is defined as the
zlopas [31]
Molarity = number of moles / volume in liters solution

Answer (4)

hope this helps!
4 0
3 years ago
Read 2 more answers
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