Draw the Lewis structure of Ne, C, and K?
Do anions gain or lose electrons? Do cations gain or lose electrons?
Draw the Lewis structure for Na+, Ca2+, O2- and Cl-.
Draw the Lewis structures for the ionic compounds below:
Na2S CaCl2,,,,Mg3N2
The Correct Answer and Explanation i
1. Lewis Structures for Ne, C, and K
- Ne (Neon): Neon is a noble gas with atomic number 10. Its electron configuration ends in 2s² 2p⁶, so it has 8 valence electrons (full octet). The Lewis structure is simply 8 dots around the symbol Ne (4 pairs of dots), representing a full octet.
..
: Ne :
..- C (Carbon): Carbon has 4 valence electrons (2s² 2p²). The Lewis structure for C has 4 single dots around the symbol, one on each side (top, bottom, left, right) representing its 4 valence electrons.
.
: C :
.(Each dot is a valence electron; total 4 dots.)
- K (Potassium): Potassium has 1 valence electron (4s¹). The Lewis structure is the symbol K with 1 dot:
K·2. Do Anions Gain or Lose Electrons? Do Cations Gain or Lose Electrons?
- Anions: These are negatively charged ions. Anions gain electrons to have more electrons than protons, resulting in a negative charge. For example, O²⁻ has gained 2 electrons.
- Cations: These are positively charged ions. Cations lose electrons to have fewer electrons than protons, resulting in a positive charge. For example, Na⁺ has lost 1 electron.
3. Lewis Structures for Na⁺, Ca²⁺, O²⁻, and Cl⁻
- Na⁺ (Sodium ion): Sodium loses its 1 valence electron to become Na⁺. So, it has no dots around Na because it lost its valence electron.
Na⁺
(no dots)- Ca²⁺ (Calcium ion): Calcium loses 2 valence electrons. No dots around Ca:
Ca²⁺
(no dots)- O²⁻ (Oxide ion): Oxygen has 6 valence electrons originally, gains 2 to complete octet, total 8 dots (4 pairs) around O, with a -2 charge.
..
: O :
..
(2-)- Cl⁻ (Chloride ion): Chlorine has 7 valence electrons, gains 1 to complete octet (8 dots), with a -1 charge.
..
: Cl :
..
(−)4. Lewis Structures for Ionic Compounds
Na₂S (Sodium sulfide)
- Na loses 1 electron to form Na⁺ (no dots).
- S gains 2 electrons to form S²⁻ (8 dots around S).
- The formula shows 2 Na⁺ for every 1 S²⁻.
Lewis structure:
- Two Na⁺ ions without dots.
- One S²⁻ ion with 8 dots (4 pairs).
Na⁺ Na⁺ :S:⁻² (with 8 dots around S)CaCl₂ (Calcium chloride)
- Ca loses 2 electrons → Ca²⁺ (no dots).
- Each Cl gains 1 electron → Cl⁻ (8 dots).
- The formula shows 1 Ca²⁺ and 2 Cl⁻ ions.
Lewis structure:
Ca²⁺ :Cl:⁻ :Cl:⁻
(8 dots) (8 dots)Mg₃N₂ (Magnesium nitride)
- Mg loses 2 electrons → Mg²⁺ (no dots).
- N gains 3 electrons → N³⁻ (8 dots).
- 3 Mg²⁺ ions balance with 2 N³⁻ ions.
Lewis structure:
Mg²⁺ Mg²⁺ Mg²⁺ :N:³⁻ :N:³⁻
(8 dots) (8 dots)Lewis structures represent the valence electrons around atoms, important for understanding chemical bonding and ionic formation. For neutral atoms like Neon (Ne), Carbon (C), and Potassium (K), dots are placed around the atomic symbols corresponding to their valence electrons. Neon has a full octet of eight valence electrons, Carbon has four, and Potassium has one valence electron.
When atoms form ions, they either lose or gain electrons to achieve a stable electron configuration, usually resembling a noble gas (octet rule). Cations are positively charged ions formed when an atom loses electrons. For example, Sodium (Na) loses its single valence electron to become Na⁺ with no valence electrons shown in the Lewis structure. Calcium (Ca) loses two electrons to form Ca²⁺, also with no valence electrons around the symbol. Conversely, anions are negatively charged ions formed when atoms gain electrons. Oxygen (O) gains two electrons to form O²⁻, completing its octet, and Chlorine (Cl) gains one electron to form Cl⁻.
For ionic compounds like Na₂S, CaCl₂, and Mg₃N₂, Lewis structures illustrate the transfer of electrons from metals to nonmetals. Sodium and calcium lose electrons to become cations, while sulfur, chlorine, and nitrogen gain electrons to become anions. The Lewis structure shows the metal ions without dots (due to electron loss) and the nonmetal ions with complete octets and their respective charges. This transfer creates an electrostatic attraction holding the ionic compounds together, stabilizing the compound.
These structures help us understand the nature of ionic bonding — metal atoms give up electrons, nonmetals accept them, resulting in a crystal lattice of alternating positive and negative ions. This is why ionic compounds tend to have high melting points and conduct electricity when molten or dissolved in water.
