Atomic Structure

What is an isotope?

Atoms of the same element with different numbers of neutrons

What is the mass number?

Total number of protons and neutrons

What is the atomic number?

Number of protons in an atom

What is atomic mass?

The weighted average mass of an element’s naturally occurring isotopes

What is electron configuration?

The arrangement of electrons in an atom’s energy levels and sublevels

What is a photon?

A packet of light energy

What is an energy level?

A specific energy an electron can have

What is an orbital?

A region around the nucleus where an electron is likely to be found

What is an excited-state electron?

An electron that has absorbed energy and moved to a higher energy level

What is the ground state?

The lowest energy arrangement of electrons

Where is most of an atom’s mass located?

In the nucleus

Which subatomic particles contribute significantly to atomic mass?

Protons and neutrons

What is the combined number of protons and neutrons called?

Mass number

Which has higher energy: ground state or excited state?

Excited state

Which is generally farther from the nucleus: a ground-state or excited-state electron?

Excited-state electron

What is the smallest possible quantity of light?

A photon

What is a quantum?

A packet of energy

What happens when an atom enters an excited state?

An electron absorbs energy and moves to a higher energy level

What happens when an electron returns to a lower energy level?

It releases energy as a photon

Why do chemicals produce different colors during flame tests?

Electrons absorb energy, move to higher energy levels, and emit light when returning to lower levels.

What is a line spectrum?

A pattern of specific wavelengths of light emitted or absorbed by an atom

How is an emission line spectrum formed?

Excited electrons drop to lower energy levels and emit photons with specific energies

Why does each element have a unique line spectrum?

Each element has unique energy-level difference

What is a Bohr model?

A model showing the nucleus and electrons arranged in energy levels

In Bohr model, how many electrons can the first level hold?

2

In Bohr model, how many electrons can the second level hold?

8

In Bohr model, how many electrons can the third level hold?

18

What did Dalton’s atomic model propose?

Atom’s are solid, indivisible spheres that couldn’t be created or destroyed.

What did the cathode ray tube experiment show?

Negatively charged electrons, showing that atoms are divisible

How did the cathode ray tube experiment change the atomic model?

Thomson proposed the plum pudding model, with negatively charged electrons in a positively charged sphere

What evidence came from the cathode ray tube?

The cathode ray deflected toward a positive plate, showing that it contained negatively charged particles

What did Rutherford’s gold foil experiment show?

Atoms have a small, solid positively charged nucleus and are mostly empty space

What evidence came from the gold foil experiment?

Most alpha particles passed through the foil, but a few bounced off

How did the gold foil experiment change the atomic model?

Rutherford disproved Thomson’s plum pudding model and proposed the nuclear model of the atom

What is the difference between the cathode ray tube and gold foil experiments?

Cathode ray tube discovered electrons while the gold foil discovered the nucleus

What did Bohr add to the atomic model?

Electrons occupy specific quantized energy levels around the nucleus

What is the correct order of the atomic models?

Dalton’s sphere, to Thomson’s plum pudding, to Rutherford’s nuclear model, to Bohr’s energy level model, to Schrodinger’s quantum mechanic/electron cloud model

How many orbitals are in each sublevel?

s=1, p=3, d=5, f=7

What do the numbers 1-7 mean in electron configurations?

The principal energy levels

What is an orbital diagram?

A diagram representing orbitals as boxes and electrons as arrows

What how many electrons can an orbital hold at most?

Two electrons with opposite spins

What is Hund’s rule?

Orbitals fill with one electron before they begin pairing

What is the speed of light in a vacuum?

3.00 × 10^8 m/s

What is the unit of wavelength?

Meters

What is the unit of frequency?

Hertz

What is Planck’s constant?

6.626 × 10^-34

As frequency increases, what happens to photon energy?

Increases

As frequency increases, what happens to wavelength

Decreases

Which visible color has the highest frequency and energy?

Violet

Which visible color has the longest wavelength?

Red

What is the relationship between wavelenth and photon energy?

Shorter wavelength means higher photon energy