chem exam 3

What is ground state?

Ground state=lowest energy electron configuration

What is excited state?

Excited state=at least one electron has absorbed energy and moved to a higher orbital

What is the order of the electromagnetic spectrum from the highest to lowest energy?

Gamma rays, X rays, UV, Visible light, IR, microwaves, FM, AM, long radio waves

Heisenberg uncertainty principle

Its impossible to know both the exact position and exact momentum (or velocity) of a particle at the same time.

The more precisely you know where a particle is, the less precisely you can know how fast and in which direction its moving and vise versa.

Aufbau Principle

an electron occupies orbitals in order from lowest energy to highest. Guides the filling of the orbitals from one element to the next. just add the new electron to what came before.

Hunds rule

every orbital in a sub level is singly occupied before any orbital is doubly occupied, all electrons in singly occupied orbitals have the same spin

Paulis rule

no two electrons in the same item can have identical values for all four of their quantum numbers. no more than two electrons can occupy the same orbital. two electrons in the same orbital must have opposite spins

Aufbau exceptions and what does it mean

cr, nb, mo, ru, rh, pd, ag, cu, pt, au. They all lose an S and get that added to the d, except Pd loses 2 from s and gives 2 to d

How does metallic chacter change in the periodic table?

Increases down, decreases across (left to right)

How does atomic size change in the periodic table

increases down, decreases across (left to right)

What are the shapes of the s, p, and d orbitals

s: sphere

p: dumbbell (3 orientations)

d:Cloverleaf (4) + 1 donut shape

What is the difference between valence and core electrons?

Valence=electrons in the outermost energy level: involved in bonding

core=inner electrons: shield valence electrons from the nucleus

What is electron affinity?

The energy change when an atom gains an electron.

Becomes more negative across a period, less negative down a group

diamagnetic vs paramagnetic

diamagnetic= electrons paired; repelled by magnetic fields

paramagnetic= unpaired electrons; attracted to magnetic fields

What are the first, 2nd, and 3rd ionization energies

1st: energy to remove first electron

2nd: energy to remove 2nd electron

3rd: energy to remove third electron

How to calculate # of radial nodes

n-l-1

how to calculate # of angular nodes

=l

What is degeneracy of a subshell

orbitals in the same sub level (same n and l) have equal energy

Gerade vs ungerade

gerade=symetric, even

ungerade=antisymetric, odd

What is kinetic energy?

Energy of motion (depends on mass and velocity)

What is potential energy?

stored energy based on position or chemical bonds

what is thermochemistry

the study of energy and heat changed during chemical reactions

what does the first law state?

energy can’t be created or destroyed, only transferred or converted. Formula: ∆E=q+w

Difference between heat and temperature

Heat (q): Energy transferred due to temperature difference

Temperature: Average kinetic energy of particles in a sample

Open system can:

exchange matter and exchange energy

Closed system can:

can’t exchange matter, but can exchange energy

Isolated system:

Can’t exchange matter or energy

Formula for change in internal energy

∆E=q+w

E represents the total internal energy of a system

What does it mean when q is negative or positive?

negative means heat was released, positive means heat was added

what does it mean when w is positive or negative

positive means work done ON the system, negative means work done BY the system

What is a state function?

a property that depends only on the current state, not on the bath take.

Formula for heat (q)

q=(m)(Cs)(∆T)

Formula for pressure-volume work

w=(-P)(∆V)

work is negative when gas expands

Thermal Energy transfer (metal in water) formula

-qmetal=qwater

Enthalpy Change (∆H)

∆H=∆E+P∆V

At a constant pressure: ∆H=qp

Hess’s law

if a reaction occurs in steps, the total ∆H is the sum of all step enthalpies

Define bond energy

energy required to break 1 mole of a chemical bond in the gas phase