Chapter 7 Review- CHE1210: Exam #2

What is electromagnetic radiation?

Type of energy in the form of waves. Light is and it's frequencies are an example of it.

What is the electromagnetic spectrum?

Shows the frequency and wavelength of all visible and invisible light.

What is the relationship between frequency and wavelength on the EM spectrum?

They're inversely related.

(Longer wavelength = less frequency)

(Smaller wavelength = more frequency)

On the visible colors on the EM, which colors have highest and lowest wavelength?

Purple has the smallest wavelength (400 nm)

Red has the highest wavelength (700 nm)

T/F: EM spectrum includes more than just visible light. It also includes waves from x-rays, radio waves, and TV waves.

True

Which of the following have very high wavelength/are high up on EM scale?

A. Radio waves

B. X-rays

C. Ultraviolet rays

D. The color yellow

A. Radio waves

(Check slide 9 for full chart)

Which of the following have very low wavelength/are low on EM scale?

A.Radio waves

B. X-rays/gamma rays

C. Infared rays

D. The color red

B. X-rays/gamma rays

(Check slide 9 for full chart)

Early theory believed that energy of light and photons were ____.

Quantized

What does it mean for energy to be quanitzed?

Given E= nhv

Elements can only increase/decrease in energy in multiples of hv.

What happens when electrons absorb photons/light energy (according to early theory)

The electrons are raised to a higher energy level (to a higher n)

Why did Bohr's model fail?

Could not predict the spectrum for multi-electron atoms (He and beyond)

Quantum Numbers:

What is n?

The principle quantum number (energy level)

Determines the size of orbital

What is ℓ?

Angular momentum quantum number (determines shape of orbital)

What is mℓ?

Magnetic quantum number (determines orientation of orbital)

What is Ms?

Spin quantum number (two possible directions of spin)

What are the two possible directions of spin?

+1/2 (spin north)

-1/2 (spin south)

Given the value of n, what formula do you use to calculate the total number of orbitals?

n^(2) = total number of orbitals

(ex. for a compound with n=3, there's 9 orbitals, 18 electrons)

Given the value of n, what formula do you use to calculate the total number of electrons across all orbitals (assuming all are full)?

2n^(2)

What is the ℓ value for s orbital?

ℓ = 0

What is the ℓ value for p orbital?

ℓ = 1

What is the ℓ value for d orbital?

ℓ = 2

What is the ℓ value for f orbital?

ℓ = 3

What is the Pauli Exclusion Principle?

Two electrons per orbital, and no electrons can have same of all 4 quantum #s

What does it mean for electrons to be diamagnetic?

Two electrons in same orbital have different, antiparallel spin

What does it mean for electrons to be paramagnetic?

Two electrons across two different orbitals next to each other have same spin.

What is Hund's rule?

Every orbital in a subshell filled with one electron before any orbital gets two.

All electrons in singly occupied orbitals have same spin.

What are valence electrons?

The electrons in shell with highest "n" value.

What does the electron cloud graph show?

The probability of finding an electron from the nucleus

(High probability = high density of electrons)

*check slide 97 for more info

What does the amplitude of the graph determine?

Higher amplitude = higher chance of finding electrons

What do the nodes mean?

The nodes mean in that area, there is a 0% chance of finding an electron.

What is the shape of the s orbital?

Spherical

T/F, as n increases, the size of s orbital and it's # of nodes increases

True

What's the formula for calculating spherical nodes?

n-ℓ-1

How much nodal planes do p orbitals have?

One (ℓ=1)

Electrons with higher principal quantum #'s (n):

A. all exist is orbitals that do not have lobes

B. move in circular orbits around the nucleus

C. have fewer subshells that they can occupy

D. have lower energy because they are closer to the nucleus

E. have higher energy because they are further away from the nucleus

E. have higher energy because they are further away from the nucleus

What is Zeff (effective nuclear charge)?

Net positive charged the outer electrons feel.

What is the shielding effect?

The core electrons shield valence electrons from attractive force of the nucleus.

The atomic radius of elements increases the more ____ or ____ you go on the periodic table.

A. Up or left

B. Up or right

C. Down or left

D. Down or right

C. Down and left.

Why does atomic radius for elements increase the more down and left you go on the periodic table?

Zeff decreases, n increases.

Which of the following statements is true?:

A. When adding an electron to an atom, its radius increases.

B. When adding an electron to an atom, its radius decreases.

C. When removing an electron from an atom, it's radius increases.

D. When removing an electron from an atom, it's radius decreases.

E. There is no relation between adding/removing electrons and an atom's radius.

A and D.

What is ionization energy?

The energy needed to remove an electron from an atom in it's GAS phase.

The ionization energy needed for elements increase the more ____ or ____ you go on the periodic table.

A. Up or left

B. Up or right

C. Down or left

D. Down or right

B. Up or right

T/F: Each time you remove an electron, more ionization energy is needed to remove the next.

True

At what point does ionziation energy drastically increase?

When you're taking an electron out of a full octet or full subshell

T/F: Ionization energy is typically positive.

True

What is electron affinity?

Change of PE when adding electron

Or the favorability of adding an electron to an atom.

The electron affinity for elements increase the more ____ or ____ you go on the periodic table.

A. Up or left

B. Up or right

C. Down or left

D. Down or right

B. Up or right

T/F: Electron affinity is typically negative, meaning it's exothermic/releases energy.

True