C Unit 4 - Electrons

What was the belief about light's behavior before 1900?

Light behaved solely as a wave.

What theory emerged that describes light's particle-like characteristics?

Quantum Atomic Theory.

What is electromagnetic radiation?

Energy that exhibits wave-like behavior as it travels through space.

What are examples of electromagnetic radiation?

Microwaves

What part of the electromagnetic spectrum can we see?

Visible light.

What is the highest point on a wave called?

Crest.

What is the lowest point on a wave called?

Trough.

What is the midline of a wave referred to as?

Origin.

What is wavelength?

The distance between two crests or troughs on a wave.

What is the symbol for wavelength?

Lambda (λ).

What is frequency?

The number of wavelengths that pass a given point in one second.

What is the unit of frequency?

Hertz (Hz).

What is amplitude?

The wave's height from crest to origin or trough to origin.

What is the speed of all forms of light?

3.00 x 10^8 m/s (denoted by the letter 'C').

How are wavelength and frequency related?

They are inversely related.

What is the photoelectric effect?

The emission of electrons from a metal when light shines on it.

Who proposed the concept of quanta?

Max Planck.

What is Planck's constant?

6.63 x 10^-34 J-s.

What is the relationship between energy and frequency?

Energy is directly proportional to frequency.

What is a photon?

A particle of electromagnetic energy with zero mass.

What happens when an electron returns to the ground state?

A photon of light is emitted.

What is an atomic emission spectrum?

A distinct color pattern emitted by a substance when electric current passes through it.

What does the quantum model explain?

The location and properties of electrons in atoms with more than one electron.

What is the formula for calculating energy of a photon?

E = h x f.

What does the term 'excited state' refer to?

When electrons are at one or more quanta above their ground state.

What is the significance of the quantum model in atomic theory?

It predicts the behavior of electrons in multi-electron atoms.

How can spectra be used in chemistry?

To identify elements based on their unique emission patterns.

What happens to energy as frequency increases?

Energy also increases.

What atomic theory was developed from the explanation of atomic emission spectra?

The Quantum Model

What significant limitation did Bohr's planetary model have?

It could only predict the atomic spectrum of hydrogen.

What does the Quantum Model predict about electrons in multi-electron atoms?

It predicts the location and properties of electrons.

What principle did Heisenberg establish regarding electrons?

It is impossible to determine both the position and velocity of an electron simultaneously.

What is the Heisenberg Uncertainty Principle?

It states that the probability solutions to the Schrodinger equations provide a likelihood of finding an electron at a given location.

What are the regions where electrons are likely to be found called?

Atomic orbitals.

How many quantum numbers are needed to describe atomic orbitals?

Four quantum numbers.

What does the Principal Quantum Number (n) indicate?

It identifies the main energy level of the orbital where the electron is located.

How many primary energy levels are possible in an atom?

Seven primary energy levels.

What does an increase in the Principal Quantum Number (n) indicate?

The electron is located further from the nucleus.

What does the Angular Momentum Quantum Number (l) signify?

It indicates the shape of the orbital.

What are the shapes of the orbital sublevels?

s (spherical)

What does the Magnetic Quantum Number (m) represent?

It signifies the orientation of an atomic orbital around the nucleus.

How many electrons can one orbital hold?

Two electrons.

What is the Spin Quantum Number?

It indicates the spin of an electron

What is Electron Configuration?

A way to express the complete arrangement of electrons around an atom.

What does the superscript in an electron configuration indicate?

The number of electrons in that sublevel.

What is the Aufbau Principle?

An electron occupies the lowest energy level possible.

What is Noble Gas Configuration?

A shorthand way to write electron configuration using a noble gas symbol.

What does Orbital Notation illustrate?

It graphically represents electron configuration and all four quantum numbers for each electron.

What is Hund's Rule?

Orbitals of the same sublevel are each occupied by one electron before any orbital is occupied by a second electron.

What is the Pauli Exclusion Principle?

No two electrons in an atom can have the same set of four quantum numbers.

What is the maximum number of electrons in the s sublevel?

2 electrons.

What is the maximum number of electrons in the p sublevel?

6 electrons.

What is the maximum number of electrons in the d sublevel?

10 electrons.

What is the maximum number of electrons in the f sublevel?

14 electrons.

How can you check the accuracy of an electron configuration?

The total of the superscripts should equal the atomic number.

What does the last segment of an electron configuration indicate?

The location of an element on the periodic table.