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What is Democritus famous for?

Credited for first formalizing a particle theory of matter
Believed all matter was made of small, indivisible particles called atoms.


What are the 6 points of Democritus' theory?

Atoms are particles in the void
Atoms are always in motion
Atoms are indivisible
Atoms come in different sizes
Atoms make life predictable
The human souls is made of soul atoms


What is John dalton most notable for? What does his model look like?

He re established the atomic theory in 1808
Explained the law of conservation of mass

It was simply just a sphere


What is daltons atomic theory?

All matter is composed of small particles called atoms
Atoms of the same element are identical
Atoms cannot be created divided or destroyed


What is JJ Thomson most notable for? What did his model look like?

He used a cathode ray tube to notice that there were negative and positive charges in an atom

His model looked like a positive sphere with floating negative particles in it
(Plum pudding)


What is Robert Millikan most notable for?

He found the mass of an electron to be 1837 times smaller then the smallest atom


What is Ernest Rutherford most notable for? What does his atom look like?

Rutherford used his thin gold sheet experiment to find that the centre of an atom is positive and called it the nucleus
He also said that electrons orbited the nucleus like planets orbit the sun

His atom had a circle centre filled with proton a while electrons orbited on lines around it (jimmy neutron logo)


What is the formula to find the speed of light?

C=(upside down y)f
C= speed of light
Upside down Y= wavelength in m
F= frequency in Hz


What is the speed of light?



What is the photoelectric effect?

When light is shined on a certain metal surface, electrons can be liberated and detected. If the frequency is too low no electrons will be emitted but if it is high enough a single photon of light is enough to liberate an electron


What is the formula used in the photoelectric effect used to calculate the energy of a photon?

E= energy of photon in J
H= planks constant in J•s
F= frequency in Hz


What is Plancks constant?

6.626 x 10^-34 J•s


What is the formula used to calculate the kinetic energy of an emitted electron?

KE=hf-ø (o with a vertical line through it)
KE= kinetic energy
h= planks constant
f= frequency
Ø= binding energy of electrons in J


What is Niels Bohr most notable for? And what did his model look like?

He proposed that electrons can occupy only certain energy levels and that the electron orbital lowest in energy is closest to the nucleus.

His model looks like current day one it has a centre nucleus with electron circle orbits around it


How do scientists determine where electrons are in an atom?

They use light or photons to knock electrons off course and create a probability cloud since you can't exactly pin down where electrons are


What are the four quantum numbers?

1. Principle quantum number
2. Angular momentum quantum number
3. Magnetic quantum number
4. Magnetic spin quantum number


What is the principle quantum number? What is its symbol?

It describes the energy level of the electron and how many orbitals you have
Represented by the letter n
N= number on the side of periodic table (row 1,2,3,4,5)
N= 1,2,3,4,5


What is the angular momentum quantum number? What is it's symbol? What are the different kinds of orbitals?

It describes the type of orbital
Represented by the letter L
S orbital - 1 balloon (circle)
P orbital- two balloon stacked (one top one bottom)
D orbital - 4 balloons ( + one coming from each corner)


What is the magnetic quantum number? What is it represented by?

Describes the orientation or shape of the orbital, ranges from -1 to +1
Represented by ml


What is the magnetic spin quantum number? What is it represented by?

Describes the spin of the electron, ranges from -1/2 to +1/2
Represented by ms


What are hadrons?

Composite particles made from quarks held together by the strong force.


What are the two types of hadrons? Examples of each?

Baryons- made from 3 quarks
Ex: protons and neutrons

Mesons- made from 1 quark and 1 anti quark
Ex: pions and Kaons


Who is the father of the periodic table?

Dmitri Mendeleev


What is atomic radii? How does it change moving across the periodic table?

It is the size of the atom

The atomic radii gets bigger moving left and down a group 👈🏼👇🏼

This is like this because elections are filling higher energy levels which are further from the nucleus (orbitals) making it bigger
There is also more protons going right across the periodic table which makes a tighter bond and decreases the size


What is ionization energy? And how does it change when we move across the periodic table? Why?

The amount of energy required to remove an electron from an atom

Ionization energy increases as we go up a group and to the right of the table 👆🏼👉🏼

Down a group decreases because electrons are further from the nucleus and shielded from positions nucleus
Across a period it increases because there is a greater positive charge attracting each electron on the same energy level


What is electron affinity? How does it change moving across the periodic table?

Is the amount of energy given off when an electron joins an atom

Electron affinity increases up a group and right across the table 👆🏼👉🏼


What is electronegativity? How does it change across the periodic table?

Is the measure of how much each atom attracts electrons in a covalent bond
It increases electronegativity up and to the right of the periodic table with fluorine being the most electronegative


Which elements are hypervalent?

Elements from the three column and down


How do you know when you just draw the Lewis structure of an ionic compound?

When it is a metal and a non metal


What does "VSEPR" stand for in the vsepr theory? What is the vsepr theory?

Valence Shell Electron Pair Repulsion

It states that the repulsion between valence electrons in molecules causes their atoms to be oriented as far apart as possible