Electrons, Bonding and Structure Flashcards
What is a shell?
A group of atomic orbitals with the same principle quantum number, n.
What is a sub-shell?
A group of the same type of atomic orbitals within a shell.
What is ionic bonding?
A type of bonding caused by electrostatic attraction between oppositely charged ions, in which atoms lose or gain electrons.
What is covalent bonding?
A type of bonding formed when atoms share electron pairs between nuclei.
What is metallic bonding?
The electrostatic attraction between positive metal ions and electrons.
What is a giant ionic lattice?
A three dimensional structure of oppositely charged ions held together by strong electrostatic forces of attraction (ionic bonds).
What is a giant covalent lattice?
A three dimensional structure of atoms bonded together by strong covalent bonds
Do ionic lattices conduct electricity?
When melted or dissolved in water, the ions are free to move and carry charge but when solid, they do not conduct electricity.
What is the solubility of ionic lattices?
They dissolve in polar solvents such as water into there respective ions.
What is a dative covalent bond?
A bond formed by a shared pair of electrons that has been produced by one of the bonding atoms only.
What are the physical properties of simple molecular structures?
- Low melting and boiling points
- Do not conduct electricity
- They are soluble in non-polar solvents like hexane
What are the physical properties of giant covalent structures?
- High melting and boiling points
- Do not conduct electricity except graphite
What are the five shapes of molecules in increasing order of size?
Linear, trigonal planar, tetrahedral, trigonal bi-pyramid, octahedral.
What are the bond angles of each molecule shape?
Linear- 180° Trigonal planar- 120° Tetrahedral- 109.5° Trigonal bipyramid- 90° and 120° Octahedral- 90°
How does a lone pair change the bond angle of a molecule?
Each lone pair, reduces the bond angle by about 2.5°.
What is electronegativity?
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.
What are intermolecular forces?
The attractive forces between neighbouring molecules to atoms.
What are permanent dipole-dipole interactions?
A weak attractive force between permanent dipoles and permanent dipoles or induced dipoles in neighbouring polar molecules.
What are London (dispersion forces)?
Attractive forces between induced dipoles in neighbouring molecules.
What are hydrogen bonds?
Strong permanent dipole-dipole interactions between electron-deficient hydrogen atoms and other molecules and a lone pair of electrons on a highly electronegative atom on a different molecule.
Why is ice less dense than water?
When ice forms, water molecules are arranged in an orderly pattern and hydrogen bonds form between the molecules. This means ice has an open lattice and when the rigid bonds collapse, the molecules can move closer together.
Why does water have higher than expected boiling points?
Hydrogen bonds are much stronger than other intermolecular forces causing it to exhibit higher melting and boiling points than other similar structures.
