U9 - Molecules + covalent bonds Flashcards
What is a covalent bond
When non-metals bond with each other sharing outer shell electrons
What is the product of a covalent bond
a molecule
Def: Covalent bond
electrostatic attraction between nuclei of atoms and shared electrons between those atoms
Def: Homonuclear
2 atoms of same element
H2
Def: Heteronucleur
2 atoms of different elements
HCl
Diatomic molecules are what type of molecules
Homonuclear
What is the bonding pair of electrons
Electrons that are shared in a bond between two elements.
What are Lone pair (single pair) of electrons
electrons are not involved in a chemical bond.
Why do All electron pairs repel each other
- Electron pair repulsion between lone pairs of electrons is very strong
- Electron pair repulsion between lone pairs and bonding pairs of
electrons is slightly weaker. - Electron pair repulsion between bonding pairs of electrons is the
weakest.
What is the direct result of electron pair repulsion
molecules will have very specific shapes
* CO2 Linear
* H2O V-shaped
* NH3 Pyramidal
* CH4 Tetrahedral
Differences between ionic and covalent compounds
Ionic……………………………………..
*Hard brittle solids
*High melting and boiling points
* Will conduct electricity in the melted or dissolved state, but not in the solid state
* Many are water soluble
Covalent…………………..
*Soft solids, liquids of gases
* Low melting and boiling points
* Low volatility
* Poor conductors
* Mostly not soluble in water
What are Allotropes
Different crystalline structures for the same element
Carbon has various allotropes
Buckministerfullerine C60
Diamond
Graphite
Explain what fullerenes are (Buckminsterfullerine)
Homonuclear allotropes of carbon
Spherical or tube like
Explain Spherical fullerenes
contains 60 carbons and are called buckminsterfullerine
