draw 2 Lewis Structures of SeOF2

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draw 2 Lewis Structures of SeOF2. one following the octet rule and one not. Use formal charge on both structures to determine which one is more stable

Which of the following is the ground state electron configuration of a calcium atom?

a. [Ne]3s2

b. [Ne]3s23p6

c. [Ar]4s13d1

d. [Ar]4s2

e. [Ar]3d2

The Correct Answer and Explanation is :

1. Lewis Structures of SeOF₂

Let’s first draw the Lewis structures for SeOF₂, where selenium (Se) is in the center, bonded to one oxygen (O) and two fluorine (F) atoms.

A) Structure Following the Octet Rule

In the octet rule, atoms typically need 8 electrons in their valence shell (except for hydrogen and some larger atoms like sulfur and phosphorus).

  • Selenium (Se) has 6 valence electrons.
  • Oxygen (O) has 6 valence electrons.
  • Each Fluorine (F) has 7 valence electrons.

Now, we distribute the electrons:

  • Se will form single bonds with O and F atoms, using 2 electrons for each bond.
  • The remaining electrons will fill the valence shells of the atoms.

Octet Structure:

     F
     |
O--Se--F
  • Each fluorine atom has 3 lone pairs, satisfying the octet.
  • Oxygen has 2 lone pairs, satisfying the octet.
  • Selenium will have a lone pair after the bonds, but it can hold more than 8 electrons since it is in the 4th period.

This structure follows the octet rule for oxygen and fluorine but breaks the octet rule for selenium. However, the selenium atom can handle more than 8 electrons in its valence shell.

B) Structure Breaking the Octet Rule

Selenium, being in period 4, can expand its octet and accommodate more than 8 electrons.

  • In this case, selenium may form double bonds or have more than 8 electrons in its valence shell.

Expanded Octet Structure:

     F
     |
O==Se==F

Here, selenium shares more electrons with oxygen, allowing it to have an expanded octet.

Formal Charge Comparison:

  • In the first structure (octet rule followed), the formal charges are minimal.
  • In the second structure (expanded octet), selenium carries a formal charge of 0, oxygen carries a formal charge of 0, and the fluorine atoms still have a formal charge of 0.

The structure following the octet rule is likely the most stable, as the atoms have the smallest formal charges.

2. Ground State Electron Configuration of Calcium

The correct electron configuration for calcium (Ca) can be determined by looking at its atomic number and the order in which electrons fill orbitals.

  • Atomic number of calcium (Ca) = 20, so a neutral calcium atom has 20 electrons.
  • The electron configuration is built by filling the orbitals in order of increasing energy: 1s, 2s, 2p, 3s, 3p, 4s.

Using this order:

  • 1s² (2 electrons)
  • 2s² 2p⁶ (8 electrons)
  • 3s² 3p⁶ (8 electrons)
  • 4s² (2 electrons)

So, the electron configuration for calcium is:

[Ar] 4s²

This corresponds to Option D.

Explanation:

  • The configuration starts with [Ar], which represents the electron configuration of argon (18 electrons).
  • After argon, we have two more electrons, which go into the 4s orbital, leading to the final configuration of [Ar] 4s².

Therefore, the ground state electron configuration of a calcium atom is [Ar] 4s² (Option D), and this configuration represents the most stable arrangement of electrons for a neutral calcium atom.

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