2.2.5 The concept of metallic bonding &delocalized electrons

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Cards (56)

What is metallic bonding?
Sharing of outer electrons in metals
How can the packing arrangements shown be used in real-world applications?
Hexagonal closest packing is used in the structure of graphite and some metals
Cubic closest packing is used in the structure of many metals and ionic crystals
Body-centered cube is used in the structure of some metals and alloys
What creates the 'sea of electrons' in metallic bonding?
Freely moving outer electrons among metal atoms
What is the significance of delocalized electrons in metals?
Move freely throughout the metal lattice
Create a 'sea' of negatively charged particles
Hold positive metal ions together
Allow efficient conduction of electricity
What are delocalized electrons in metallic bonding?
Outer electrons that move freely in the lattice
What are the key differences between hexagonal closest packing and cubic closest packing?
Hexagonal closest packing has a higher packing density than cubic closest packing
Hexagonal closest packing has a more efficient use of space compared to cubic closest packing
Hexagonal closest packing results in a more stable and rigid structure compared to cubic closest packing
How do delocalized electrons contribute to metallic bonding?
They create a 'sea' of electrons holding ions together
What is the name of the model shown in the image?
Electron Sea Model
How do delocalized electrons contribute to metallic bonding?
They are attracted to positive metal ions
What are the four types of chemical bonding described in the image?
Ionic
Simple covalent
Network covalent
Metallic
Why do metallic substances conduct electricity well?
Electrons move freely between atoms
Why are metallic substances malleable?
Metal ions slide past each other easily
What is the significance of the 'sea of electrons' in metallic bonding?
It allows metals to conduct electricity and heat
What are the properties of metals explained by metallic bonding?
Hardness & Strength
Conductivity
Malleability & Ductility
Luster
How do the mechanical properties like tensile strength, stiffness, and toughness differ across the four bonding types?
Ionic: Very low tensile strength, high stiffness, low toughness
Simple covalent: Low tensile strength, low stiffness, medium-high toughness
Network covalent: Very high tensile strength, very high stiffness, low toughness
Metallic: High tensile strength, high stiffness, very high toughness
How does thermal conductivity occur in metallic substances?
Heat transfers through electron movement
What are the steps in the bonding process of metallic bonding?
Metal atoms lose outer electrons
Electrons move freely through lattice
Positive ions are held together by electron 'sea'
What are the three main arrangements of metallic structures?
Hexagonal closest packing
Cubic closest packing
Body-centered cubic
How do delocalized electrons contribute to the packing of metal ions?
They allow metal ions to pack closely together
What is the significance of delocalized electrons in a molecule?
Delocalized electrons are not confined to a single bond or atom
They can move freely throughout the molecule
This allows for increased stability and reactivity
How do delocalized electrons spread out in a metal lattice?
Start from distinct orbitals
Move freely across the structure
Form a continuous 'sea' of electrons
What type of particles are represented by the red "+" symbols in the Electron Sea Model diagram?
Positively charged metal ions
What is the name of the packing arrangement shown in part a of the image?
Hexagonal closest packing
Why do metal atoms pack closely together in a metallic lattice?
To maximize attractive forces from shared electrons
What is the name of the packing arrangement shown in part c of the image?
Body-centered cube
What is the name of the molecular structure shown on the left?
6 p-orbitals
What is the key difference between the two molecular structures shown?
The structure on the right is delocalized, while the one on the left has 6 p-orbitals
How does the Electron Sea Model differ from the ionic bonding model?
Ionic bonding involves the complete transfer of electrons between atoms, forming positively and negatively charged ions.
Metallic bonding in the Electron Sea Model involves the delocalization of valence electrons, forming a "sea" of electrons around the positively charged metal ions.
How do delocalized electrons affect the conductivity of metals?
They allow efficient movement and conduction of electricity
What are the key properties of metals that the Electron Sea Model explains?
High electrical and thermal conductivity
Malleability and ductility
Metallic luster
What surrounds the positively charged metal ions in a metallic lattice?
A sea of electrons
What holds the positive ions together in metallic bonding?
The electron 'sea' created by free electrons
What is the structure that explains the properties of metals?
Metallic bonding
What role does electrostatic attraction play in metallic bonding?
It holds metal atoms together like glue
How do metal atoms bond in metallic bonding?
They share their outer electrons across a lattice
What are the properties of metallic substances?
Electrical conductivity: Electrons move freely between atoms
Thermal conductivity: Heat transfers through electron movement
Hardness: Metal lattice structure provides strength
Luster: Electrons reflect light efficiently
Malleability: Metal ions slide past each other easily
What is the definition of a p-orbital?
A type of atomic orbital with a dumbbell shape
Electrons in p-orbitals have angular momentum
p-orbitals are higher energy than s-orbitals
What is the name of the packing arrangement shown in part b of the image?
Cubic closest packing
What gives metals their luster?
Delocalized electrons reflect light
Why do metals exhibit hardness and strength?
Due to strong attraction between metal ions and delocalized electrons