Last Unit of Chemistry (Periodic Table Unit) 1/12/26

Who came up with the term “atomos?”

Democitrus

Law of Conservation of Mass:

Mass can not be created nor destroyed

Law of Definite Proportions:

Cmpds contain elements in definite proportions

Who came up with the first model of the atom:

John Dalton

Who used the Cathode Ray Tube to determine positive and negative charges in an atom?

J.J. Tomson

Who came up with the plum pudding model with electrons scattered around?

J.J. Tomson

Who conducted the Gold Foil Experiment?

Ernest Rutherford

What was the theory determined after the Gold Foil Experiment was conducted?

Matter is empty space with a dense, positive nucleus

Wavelength is best defined as:

distance between identical points in a wave (represented by λ)

Who found Mass of electrons to be 1/2000 the mass of hydrogen?

Robert A. Milikan (also known for the oil-drop experiment)

Frequency is best defined as:

NUMBER of waves that pass a point per second (represented by 𝜈)

What is the equation that equals the speed of light in waves:

c= wavelength * frequency

What does the speed of light equal:

C= 3.0 × 10⁸ m/s

What is the equation for frequency in waves:

Frequency= speed of light/wavelength

What is the equation for energy of a quantum:

h(planks constant) * frequency

Who was the Danish physicist who proposed a model of the atom where the electrons were in fixed orbits (Planetary Model)?

Neils Bohr

Give the max number of electrons from each energy level in the Bohr Model:

n=1 ——- 2 electrons

n=2 ——- 8 eletrons

n=3 ——- 18 electrons

n=4 ——- 32 electrons

Can an electron jump to different orbits?

YES

Can an electron gain or lose energy WHILE IN ORBIT?

NO

Who discovers the neutron and was also a student of Rutherford?

James Chadwick

What is the Photoelectric Effect?

When light of a particular frequency shines on a metal, electrons are given off that metal

Who proposed that object absorb energy in packets called “Quanta”

Max Planck

Who suggested the idea that light energy has a dual nature? Light can have properties of waves and can be thought of as a stream of particles(photons)

Albert Einstein

What was the question that Louis deBrogile asked about quantum mechanics, and what was the answer?

Can particles of matter have properties of waves? YES

Who came up with the uncertainty principle and what does it state?

Heisenberg’s principle states that when an electron is hit with light, its position changes

Who made the equation that determines the location of an electron?

Erwin Schrodinger

How many quantum numbers are described in orbitals?

4

What is the mathematical representation of where an electron is?

Atomic orbitals

What are the different types of orbital shapes? Also, name the maximum number of electrons each orbital can have?

s- spherical (2 electrons)

d- double dumbbell (10 electrons)

p- p-nut (6 electrons)

f- complex (14 electrons)

What is the Aufbau Principle?

Must fill orbitals starting at the lowest energy and then working up to the highest energy

Pauli Exlusion Principle:

No 2 electrons can have the same spin quantum number (so when doing an orbital diagram no 2 arrows can both be pointing up, one must point up then the other down)

Hund’s Rule:

One electron before any get two electrons

What are exceptions to electron configuraion:

group 6 and 11 (follow half rule where d steals from s to be half full and stable)

Who arranged the periodic table by atomic mass?

Dmitri Mendeleev

Who arranged the periodic table by the number of PROTONS?

Henry Moseley

Where are the alkali metals located?

In the first column of the table

Where are the alkaline earth metals located?

Second column

What is the trend for atomic radius in the periodic table?

As you go left to right, radius decreases

As you go top to bottom, radius increases

What is Ionization energy and what is the trend for it in the periodic table?

Ionization energy is energy used to remove an electron from and atom

Left to right, Ionization energy increases

Top to bottom, Ionization energy decreases

What element is the most electronegative element?

Fluorine (electronegativity increases going up and right)

Reactivity trend:

Left to right, reactivity increases

Top to bottom, reactivity decreases

What are the 4 quantum numbers:

Principle, magnetic, spin, shape