Draw the Lewis dot diagram for the phosphorus atom

  1. Draw the Lewis dot diagram for the phosphorus atom.
  2. Draw the Lewis dot diagram for the COs ion.
  3. Give the electron configuration (1s22s2….) for the Mg ion.
  4. Which has the larger radius For F¹?
  5. Which has the larger radius, Ca or Ca?
  6. Arrange in order of increasing ionic radius (smallest to largest): 11, Cs”, Te
    Give the Lewis dot diagram for the covalent compound SnCls
  7. Arrange in order of lowest to highest electronegativity – O, P, N
  8. Given these electronegativities (Si= 1.8, O=3.5, C=2.5, Br2.8, As = 2.0) which of these bonds is most polar?
    a) Si-O
    b) C-Br
    c) As-Br
  9. Write 2 resonance structures for the formate ion [NO:

The Correct Answer and Explanation is :

Let’s break down each question one by one:

1. Lewis Dot Diagram for the Phosphorus Atom

Phosphorus (P) has an atomic number of 15, meaning it has 15 electrons. In its neutral state, it would have:

  • 5 valence electrons (since it is in Group 15 of the periodic table).
  • The Lewis dot diagram for phosphorus (P) will have 5 dots around the symbol P to represent these 5 valence electrons.

Diagram:

   P
  :   :

2. Lewis Dot Diagram for the CO₃²⁻ Ion (Carbonate Ion)

The carbonate ion (CO₃²⁻) consists of one carbon (C) and three oxygen (O) atoms with an overall 2- charge. The Lewis structure involves:

  • Carbon having 4 valence electrons.
  • Oxygen having 6 valence electrons each (total of 18 for three oxygens).
  • 2 additional electrons for the 2- charge.

Diagram:

       O
      ..
   O=C-O
      ..

The central C atom is double-bonded to one oxygen and single-bonded to the other two oxygens, each with a negative charge. The negative charges are delocalized.

3. Electron Configuration for the Mg²⁺ Ion

The magnesium ion (Mg²⁺) forms by losing two electrons. Magnesium has an atomic number of 12, and its neutral configuration is 1s² 2s² 2p⁶ 3s². After losing two electrons, the configuration becomes:

Electron configuration for Mg²⁺:

1s² 2s² 2p⁶

This is the same as the noble gas Neon (Ne).

4. Which has the larger radius, F⁻ or F?

The F⁻ ion is larger than the neutral F atom because it has gained an electron. The addition of an electron increases the electron-electron repulsion, causing the electron cloud to expand.

5. Which has the larger radius, Ca or Ca²⁺?

The neutral Ca atom (Calcium) has a larger radius than the Ca²⁺ ion because the Ca²⁺ ion has lost two electrons, resulting in a higher effective nuclear charge pulling the remaining electrons closer to the nucleus.

6. Order of Increasing Ionic Radius (smallest to largest): Na⁺, Cs⁺, Te²⁻

In general, ionic radius increases as you move down a group and decreases across a period. Among these ions:

  • Na⁺ has the smallest radius because it has lost an electron.
  • Cs⁺ is larger than Na⁺ because it’s further down the periodic table.
  • Te²⁻ is the largest because it gained two electrons, increasing its size significantly.

Order: Na⁺ < Cs⁺ < Te²⁻

7. Lewis Dot Diagram for the Covalent Compound SnCl₄ (Tin Tetrachloride)

Tin (Sn) has 4 valence electrons and each chlorine (Cl) has 7 valence electrons. In SnCl₄, tin forms 4 covalent bonds with chlorine atoms.

Diagram:

    :Cl:
     |
Cl:Sn:Cl
     |
    :Cl:

8. Electronegativity Order (lowest to highest): O, P, N

Electronegativity increases across a period and decreases down a group. So:

  • P has the lowest electronegativity.
  • N is more electronegative than P.
  • O has the highest electronegativity.

Order: P < N < O

9. Most Polar Bond Based on Electronegativity Values:

Given electronegativities:

  • Si = 1.8
  • O = 3.5
  • C = 2.5
  • Br = 2.8
  • As = 2.0

The most polar bond will have the largest electronegativity difference.

a) Si-O: ΔEN = 3.5 – 1.8 = 1.7
b) C-Br: ΔEN = 2.8 – 2.5 = 0.3
c) As-Br: ΔEN = 2.8 – 2.0 = 0.8

Most polar bond: Si-O

10. Resonance Structures for the Formate Ion (HCO₂⁻)

The formate ion (HCO₂⁻) has a negative charge and consists of a central carbon bonded to two oxygens, one of which is single-bonded (and carries the negative charge) and the other double-bonded.

Resonance structures:

     H        H
      \       /
       C = O       ↔       C - O⁻
      /                       ||
     O

These two structures represent the delocalization of the negative charge and the electron distribution in the molecule.

In summary:

  1. Phosphorus has 5 valence electrons.
  2. The CO₃²⁻ ion has delocalized bonds and charge.
  3. Mg²⁺ configuration is 1s² 2s² 2p⁶.
  4. F⁻ has the larger radius than F.
  5. Ca has the larger radius than Ca²⁺.
  6. Order of ionic radii: Na⁺ < Cs⁺ < Te²⁻.
  7. SnCl₄ has single bonds with chlorine atoms.
  8. Electronegativity order: P < N < O.
  9. Si-O bond is the most polar.
  10. The formate ion has resonance structures showing delocalized electrons.
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