chemistry - test #1

J.J Thompson

J.J Thompson

Using the Cathode Ray Tube, discovered the first subatomic particle (the electron).

Robert Milikan

Using the oil drop experiment, determined the mass of an electron

Ernst Rutherford

Using the Gold Foil Experiment discovered the nucleus (proton), the electron orbital theory, and that the atom is mostly empty space.

James Chadwick

confirmed the existence of the neutron (part of the manhattan project)

Max Planck

Originator of the Quantum Theory: energy can be released/abosrbed by atoms in discrete chunks (photons) of some minimum size. Energy is quantized "E=hv" - minimum quantum of his equation can be like 6 times or 4 times.

Albert Einstein

Says light behaves lke a particle and proves Plank correct that energy is quantized in photons and restricted, uses the photoelectric effect.

Niels Bohr

ELECTRONS GET EXCITED!! Energy is involved in moving an electron from one level to another. Electron is in ground state and then gets heated (absorbed eNeRgY) moves to excited state and when it moves back to ground state it produces light energy. Electrons cannot live between the energy levels Proposed 1st plausible thoery of electronic structure

why dont we experience quantization of energy

because they electrons are much smaller than we are

Werner Heisenberg

the uncertainty principle: you can either know the speed (momentum) or position of subatomic particles (electrons), but you can not know both at the same time. The act of observing them alters/destroys subatomic events.

electron is so small that the energy it takes to measure the electron will disturb position/velocity

what is quantum physics/ quantum mechanics? Orginator?

quantum mechanics: a complex mathematical way of describing how electrons work quantum physics: a set of physics that governs the behavior of particles at the atomic and subaotmic level originator: plank

Louis de Broglie

suggested that particles (electrons) exhibit wave like properties.

Devinson and Germer

cofirms de Broglie's theory that electron acts like a wave as it orbits

Erwin Schrodinger

-helped understand how an object can be both a particle and a wave -using complex mathematical equation to describe its behavior.( proved de Broglie correct) -subatomic particles can disappear and reapperar in another place

• equation correctly described the motion and behavior of electrons in all elements

Aufhau principle?

Electron build up process, you can't skip energy levels!!

Hund's Rule

spread out electrons over available orbitals all with the same spin. When pairing, MUST have opposite spins. Unpaired electrons have the same spin

Electron Configuration

1s^2, 2s2, 2p^6, 3s^2, 3p^6, 4s^2, 3d^10, 4p^6, 5s^2

Finding valence electrons

all the electrons in the outermost shell

Justify the existence of the Atom

It could be said that a the electron would spiral into the nucleus, causing an explosion, meaning that there would be no atom. This is false, the electron will not spiral into the nucleus because once the eletron reaches its lowest energy level, it can not go any farther. The quanitization of energy exemplfies this, explaining that the electron is retained to a specific energy level in its excited state. When it reaches the excited state it has no place to go and falls back to the ground state while releasing energy in the form of light.

We do not exhibit such energy because the electron will not spiral into the nucleus (electrons cannot live between energy levels) and is in a fixed energy state.

How do electrons give off light?

When electrons move they give off light. Energy is invloved in moving electrons from one level to another. Electron starts in ground state and then move to the excited state when they have gained enough energy to move from one level to the next. It then falls to the ground state where it releases that energy that it absorbed in the form of light .

what makes an atom magnetic

the more unpaired d electrons that it has

How are 2 electrons able to be in one orbital?

ELECTRON SPIN! when electrons spin, it creates opposite magnetic field allowing electrons to fit within an orbital though they ordinarily don't fit within an orbital because they can't "stick" (opposites attract, they are not opposites)

how is an atom stable?

if an atom is 1/2 full a d subshell or completly

n

principle quantum number

pauli's exclusion

two electrons per orbital