Honors Chemistry Unit 3 (Modern Atomic Theory)

How is the nucleus of a nuclear atom?

positively charged and dense

What structure of an atom contributes the most to the atom’s mass but very little to the atom’s volume.

the nucleus

what is the nucleus of an atom made out of?

protons and neutrons

how many nanometers does red visible light have?

700 nm

how many nanometers does violet visible light have?

400nm

list the visible light spectrum from lowest energy, frequency and longest wavelength to highest energy, frequency and shortest wavelength

red, orange, yellow, green, blue, indigo, violet

list the electromagnetic light spectrum from lowest energy, frequency and longest wavelength to highest energy, frequency and shortest wavelength

radio waves, micro waves, infrared radiation, visible light, ultraviolet light, x-rays, gamma rays.

what is wavelength

the length of a wave (m,cm,nm,…)

what is wavelength’s variable

λ (lambda)

what is the unit for wavelength when solving for wavelength?

meters (m)

what is frequency

the number of waves that pass a fixed point in 1 second

what is frequency’s variable

ν (nu)

what is the unit for frequency when solving for frequency?

Hertz (Hz)

What two things of a wave are inversely related

wavelength and frequency

what two things of a wave are directly related

speed and energy

what is speed

all ave energy that travels at the speed of light

what is the variable for speed

c

what does speed (C) equal

speed of light (2.998 × 10^8 m/s)

how can we find speed (C)?

c = λv

what is h?

Planck’s constant (6.626 × 10^-34 J x s)

what does the variable, E, stand for?

the difference in energy levels (Joule, J)

how can we find E? (there’s two equations)

E = hc/λ or E = hv

what is Avogadro’s Number?

6.022 × 10^23

what are periodic trends

recurring patterns down a group or across a period

what is atomic radius

½ the distance between the nuclei of 2 like atoms joined together (pm)

atomic size increases OR decreases down a group?

increases

why does atomic size increases down a group?

because of electron shielding (inner e-s “shield” the valence e-s from the attractive force of the nucleus)

atomic size increases OR decreases across a period?

decreases

why does atomic size increases across a period?

because of nuclear charge (as protons are added to the nucleus, there is more attractive force with the e-s)

what is ionization energy

energy required to remove and e- (kJ/mol)

does (Ei) (Ionization energy) increase OR decrease down a group

decreases

why does (Ei) (Ionization energy) decrease down a group

because of electron shielding (e-s are further from the nucleus so they are more easily removed)

does (Ei) (Ionization energy) increase OR decrease across a period

increases

why does (Ei) (Ionization energy) increase across a period

because of nuclear charge (increased positive charge of the nucleus holds e-s tighter)

In cations, what happens to the size of an ion when it loses a valence e-?

the resulting ion is smaller

why is the resulting ion smaller for cations?

1. the atoms loses an energy level

2. the attraction between the remaining e-s and the nucleus is increased

In anions, what happens to the size of an ion when it gains a valence e-?

the resulting ion is larger

why is the resulting ion larger for anions?

the attraction of the nucleus for any one e- decreases

what is an orbital

region of space where there is a 90% chance of finding an electron

what is the Heisenberg uncertainty principle

it is impossible to determine with certainty the location and momentum of a particle

do electrons hang out in orbits or orbitals?

they hang out in orbitals

How many quantum #s are there?

4

What is the 1st quantum # called?

Principal quantum number

what variable (letter) stands for the “principal quantum #”?

n

Principal quantum number

(energy level) describes the main energy level in which the electron is located

What is the 2nd quantum # called?

Angular momentum number

what variable (letter) stands for the “angular momentum #”?

swirly l 

angular momentum number

(sublevel) describes the shape of the orbitals

s-sublevel orbital looks like…

sphere

p-sublevel orbital looks like…

dumbell

d-sublevel orbital looks like…

double dumbbell

f-sublevel orbital looks like…

bunch o’ balloons

What is the 3rd quantum # called?

magnetic quantum number

what variable (letter) stands for the “magnetic quantum  #”?

m

magnetic quantum number

(orbitals/orientations) describes the number of orbitals per sub level

s-sublevel has how many orbitals?

1

p-sublevel has how many orbitals?

3

d-sublevel has how many orbitals?

5

f-sublevel has how many orbitals?

7

What is the 4th quantum # called?

spin quantum number

what variable (letter) stands for the “spin quantum #”?

m subscript s

spin quantum number

(spin) describes the “spin” of an electron

what are the two possible values for the spin quantum #?

-1/2 and ½ (spin up or down)

Pauli exclusion principle

maximum of 2 electrons per orbita (opposite spins)

Hund’s rule

the most stable arrangement has a maximum # of unpaired electrons (Thanksgiving rule)

Aufbau principle

electrons will occupy the lowest energy orbital available (electrons are lazy)

an orbital is designated by…

its energy level (n) and its sub level (l)

Aufbau Chart

what are valence electrons

electrons in the outermost energy level (involved in bonding)

what do orbital diagrams show?

What do electron configurations show

They show how electrons are arranged in an atom

what are the aufbau exceptions (elements) in electron configurations?

Chromium (Cr) and Copper (Cu)

for shorthand electron configuration, where would you need to go first?

to the last noble gas

what is periodicity

a repeating pattern

who arranged the 63 elements by increasing atomic mass

Dmitri Mendeleev

what was a trend in Mendeleev’s periodic table

elements with similar properties fell into the same group

why did Mendeleev leave empty spaces on his periodic table

for elements that have not yet been discovered

Ekasilicon, predicted by Mendeleev, was later discovered as…

Germanium in 1886

who arranged the elements by # of protons

Henry Moseley

what are the groups (families) of the periodic table?

columns of the periodic table (1-18)

elements in the same group have what in common? (2 things)

1. have similar chemical properties

2. the same # of valence electrons

what do valence electrons determine?

chemical properties

what are the periods of the periodic table

rows of the periodic table (1-7)

elements in the same period have the same…

valence energy level

alkali metals

1. group 1 metals (NOT HYDROGEN)

2. soft metals, very reactive

3. 1 valence electron in s-sublevel (ns1)

4. form 1+ ions

5. react with water to form a base and hydrogen gas 

alkaline earth metals

1. group 2 metals

2. harder, stronger, denser than alkali metals

3. react with water (not as reactive as alkali metals)

4. 2 valence electrons in s-sublevel (ns2)

5. Form 2+ ions

halogens

1. group 17, non-metals

2. “salt formers” (especially with group 1 & 2 metals)

3. very reactive

4. 7 valence electrons (ns2 np5)

5. Form 1- ions

noble gases

1. group 18, non-metals

2. 8 valence electrons (ns2 np6)

3. filled with s & p sub levels = STABLE electron configurations

4. uncreative (also known as inert)

5. snobs of the periodic table (they don’t like to mix with other elements)

6. DO NOT FORM IONS

when electrons absorb energy, what happens

electrons wil move up from the ground state to an excited state

when electrons move back down to the ground state, what happens

electrons will release energy as a photon of light

what does the type of light depend on

it depends on the energy difference between the excited state and the ground state

light is…

a wave

when constructive interference happens during a double slit experiment, what’s happening 

crests align with other crests and troughs align with other troughs from other waves 

when destructive interference happens during a double slit experiment, what’s happening 

crests and troughs align

light is not only a wave, it’s also…

a particle!

what is a photon

a particle of light with a. specific amount of energy

what is Bohr’s atom model?

electrons exist in energy levels that are certain distances from the nucleus (orbits)

how is the energy of electrons?

they’re quantized

can electrons exist between energy levels?

no

what is a “quantum” of energy

the amount of energy absorbed or released to change energy levels