Thermo Chem
When does atomic radius increase?
when you move down a group
What is an energy level?
fixed distance from nucleus where electrons are found
What is an atomic radius?
the size of its atoms
Are negative or positive ions bigger than the 'parent' atom? why?
negative - because electrons are added, extra e-s increase electron repulsion hence expanding the ion
What is ionisation energy?
The energy needed to remove an electron from each atom in one mole of gaseous atoms
What is electronegativity?
Measure of how strongly an attom attracts a bonding pair of electrons
What is polar?
A difference in electronegativity between atoms
What is an ionic bond?
force between a positive and negative ion
Why are the mp/bp of ionic substances so high?
electrostatic forces are not easily overcome
What is the polarity of an ionic substance?
polar
What is a temporary dipole?
Asymmetric distribution of electrons
How do temporary dipoles work?
inc of e-s on one side = higher e density
How does the size of an atom affect temporary dipoles?
larger atoms have more electrons = stronger td as more e available
How does shape affect temporary dipoles?
linear = more surface area, electrons are closer
Temporary dipoles occur in which type of molecule?
non-polar
When are permanent dipoles formed?
When two atoms with a large difference in electronegativity bond
Where are permanent dipoles found?
In polar molecules
What elements do hydrogen boding occur with?
FON
What kind of bonds are hydrogen bonds?
intermolecular bond
Why is the hydrogen bond so strong?
Large difference between electronegativity
When will a molevule dissolve in a solvent?
when active forces of solvent are stronger than molecule
What is entropy?
amount of order or disorder within a substance
What does Hess's Law state?
total amount of change during reaction is same whether reaction is completed in one or several steps
How many shapes are there in thermochemistry L3?
12