Unit 5 Flashcards
Which known elements exist diatomically in nature?
N2, O2, F2, Cl2, Br2, I2, H2
Mole
A counting number
Avogadros number
1 mol: 6.02 x 10^23 items
Representative Particle
the smallest unit in which a substance naturally exists.
atoms – the smallest particle of an element.
ions – atoms with positive or negative charges.
molecules – two or more covalently bonded atoms.
formula units – the simplest ratio of ions that make up an ionic compound.
Is a Molecule
Polar or NonPolar?
Are all the atoms attached to the central atom the same?
yes: ask question 2
no: likely polar
The greater the EN…
the more polar is the bond.
Is a Molecule
Polar or NonPolar?
Are there lone pair electrons on the Central atom?
No: Non polar
yes: polar
exceptions:
Except 5 Total pairs with 2 Bonding & 3 Non-bonding
(MG: Linear)
Except 6 Total pairs with 4 Bonding & 2 Non-bonding
(MG: Square planar)
Molecule
Group of atoms held together by Covalent Bonds
Intramolecular Forces
Within one molecule
Inside Molecules (Covalent)
Intermolecular Forces
Are In Between Molecules
DEPENDS on whether the Molecule is
POLAR or NONPOLAR
Intermolecular Forces Are Weakest in substances that are _______ at RT
And
Strongest in substances that are _______ at RT
Intermolecular Forces are weakest in substances that are Gases at RT
And
Strongest in substances that are Solids at RT
If Intermolecular Forces are STRONG, then the Boiling Point will be at a ______ Temperature.
If IMFs are STRONG, then the Boiling Point will be at a HIGHER Temperature.
What type of Intermolecular forces do non polar molecules have?
Only have London Dispersion Forces (LDF)
Generally weak
Can become stronger as size of the molecule increases
What type of Intermolecular forces do polar molecules have?
Have London Dispersion Forces
Also -have Stronger Dipole-Dipole forces
AND Molecules wih H covalently bonded to F, O or N have a special type of D-D force called Hydrogen Bonding (chem is FON)
For a molecule to be polar the difference in EN has to be ____ or greater.
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