Chemistry Unit 2 (copy)

IB chem test study unit 2 by katie on 4/30. Not sure how deep we have to go into the essential question, "How has atomic theory changed over time?". Will ask Ms.Ravo.... someone remind me pls

John Dalton 1803

Made Democritus’ idea into a theory. Matter is composed of atoms, atoms of the same element are identical, atoms combine in whole numbers to create compounds. A reaction rearranges atoms

JJ Thompson

Discovers electron, and its negative charge (first subatomic particle, and Dalton is wrong). Proposed that cathode rays were streams of particles much smaller than atoms.

PLUM MODEL shows neg electrons in a pool of pos electrons.

Atom

smallest thing of an element that shows all the characteristics of that element. electrically NEUTRAL

Ernest Rutherford: Gold Foil Experiment 1911

Directing alpha particles (+) to a gold foil, watching it scatter. Found most particles go straight through the foil, while some scatter, showing the existence of the nucleus, and that an atom is mostly empty space.

Bohr Model

Planetary Model, electrons travel in orbitals, each orbital has a definite energy.

Orbitals closer to the nucleus has lower energy

Schrodinger: 1926

The Wave Mechanical Model: likelihood of finding an electron at a certain place

Electrons move like particles and waves

Electrons move like….

particles AND waves

Chadwick: 1932

Discovers neutron, same mass as a proton, electrically neutral

Protons location and weight

Nucleus and 1 amu

Neutron location and weight

nucleus and 1 amu

Electron location and weight

Outside the nucleus, 0 amu

Atomic Number

number of protons

Isotopes

differing number of neutrons (carbon -12…. add mass number at the end)

Isotope Notation

top is mass # and ottom is atomic #

Ions

when protons do not equal electrons (charged)

Relative atomic mass

The average mass of an atom of an element taking into account all of its isotopes and their relative abundance (how often they show up naturally )

Energy levels/shells and their max # of e

2n² shows the maximum number of electrons that a shell can accommodate

Valence electrons

electrons in the outermost shell

Lewis electron dot structures

Showing # of valence electrons (clockwise)

Electron config

Li: 2—1

Sulfur : 2—8—6

Energy levels divided up into Sublevels/subshells, with letters…

s, 2. p , 6. d, 10 and f, 14. (max # of electrons)

FULL electron config

1s22s22p6……

exceptions when doing full electron config and WHY

Chromium and Copper, because the last sublevel is 4 or 9, and they would be happier at 5 or 10. (take one from the second to last level)

How to write condensed config

use [noble gas]

What are orbitals

region of space where there is a high chance an electron is gna be there

1s and 2s orbitals

SHPERICAL and 2s is bigger.

px, py, and pz orbitals

DUMBELL SHAPED

Orbital diagrams

most detailed e config, orbitals are boxes, arrows representing the spinning of opposite directions.

Pauli Exclusion Principle

A maximum of two electrons in each orbital, but only if they have opposite spins.

Hund’s Rule

fill in all the spaces in the boxes with one before going in for seconds,,, basically

which electrons are removed first

highest energy level, the ones furthest away from nucleus CAUSE THEY HAVE LEAST ATTRACTION

what is isoelectronic ill do this lkater damn

idfk

Proof that supports electron config?

Flame test…. we shld look more into this.

Flame test

atoms of different elements produce different flame colors when heated with a Bunsen burner, producing light of distinctive color when an electric discharge is passed through a vapor of an element.

WHY does the flame test do that…

The flame test excites electrons in atoms, causing them to release energy in the form of light at specific wavelengths, which corresponds to different colors.

Energy and frequency have a ____ relationship

direct

wavelength and frequency/energy have a ____ relationship

indirect

Continuous spectrum

White light is all the colors at once.

emission spectrum/line spectrum

light emitted by gas, only certain wavelengths of light pass

What happens to the lines as we go towards higher energy (violet)

they converge

How is the emission spectrum created

1. energy is given to the atom, where they enter the excited state

2. they fall back down to their ground state, releasing energy in the form of electromagnetic radiation. One photon (packet of energy) is released for each electron transition)

How to write excited state config

Put an electron in another level basically.

Visible light only falls to which level?

2