Chem Quiz (bohr models + light and spectrums)

What is electromagnetic radiation?

Energy that travels through space as waves.

What is wavelength (λ)?

Distance between corresponding points on a wave.

What is frequency (ν)?

Number of waves passing a point per second; measured in Hz.

What is a quantum?

A specific amount of energy that can be gained or lost.

What is a photon?

A packet of electromagnetic energy.

What is the relationship between wavelength and frequency?

Inverse; longer wavelength = lower frequency.

What is the relationship between frequency and energy?

Direct; higher frequency = higher energy.

What is the relationship between wavelength and energy?

Inverse; shorter wavelength = higher energy.

What is the EM spectrum from LOW → HIGH energy?

Radio → microwave → infrared → visible → UV → X-ray → gamma.

What is the EM spectrum from HIGH → LOW energy?

Gamma → X-ray → UV → visible → infrared → microwave → radio.

What is visible light from HIGH → LOW energy?

Violet → indigo → blue → green → yellow → orange → red.

Which visible color has the highest energy?

Violet.

Which visible color has the lowest energy?

Red.

Which visible color has the shortest wavelength?

Violet.

Which visible color has the longest wavelength?

Red.

What happens when an electron moves to a higher energy level?

It absorbs energy.

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

It emits energy as a photon.

What is absorption?

An electron gains energy and moves to a higher energy level.

What is emission?

An electron loses energy and moves to a lower energy level.

What is continuous energy?

Energy can have any value; like going up a ramp.

What is non-continuous/quantized energy?

Energy exists only at specific levels; like stairs.

What is the key idea of Bohr's model?

Electrons exist in specific energy levels around the nucleus.

Why did hydrogen's bright-line spectrum support Bohr's model?

It showed electrons can only emit specific amounts of energy.

Why does each element have a unique bright-line spectrum?

Each element has unique electron energy levels and transitions.

How do you identify an unknown from an emission spectrum?

Match the positions of its lines to reference spectra.

What does a larger energy transition produce?

Higher-energy light with higher frequency and shorter wavelength.

What is the speed of light equation?

c = λν.

What is the speed of light?

3.00 × 10⁸ m/s.

What is the photon energy equation?

E = hν.

What is Planck's constant?

h = 6.626 × 10⁻³⁴ J·s.

How do you calculate frequency from wavelength?

ν = c/λ.

How do you calculate wavelength from frequency?

λ = c/ν.

How do you calculate energy from frequency?

E = hν.

How do you calculate energy directly from wavelength?

E = hc/λ.

What unit must wavelength be in for c = λν?

Meters (m).

How do you convert nanometers to meters?

Multiply by 10⁻⁹.

What happens to wavelength when frequency increases?

Wavelength decreases.

What happens to energy when frequency increases?

Energy increases.

What is the photoelectric effect?

Light ejects electrons when photons have enough energy.

Why can violet eject electrons but red cannot?

Violet has higher frequency and higher photon energy.

What does dual wave-particle nature of light mean?

Light behaves as both waves and particles (photons).

In an emission transition, which direction does the electron move?

Higher energy level → lower energy level.

In an absorption transition, which direction does the electron move?

Lower energy level → higher energy level.

What happens in E₂ → E₁?

Emission.

What happens in E₁ → E₃?

Absorption.

Which has greater energy: a short or long wavelength?

Short wavelength.

Which has greater energy: high or low frequency?

High frequency.

What is a Bohr model?

A model showing electrons in specific energy levels around the nucleus.

How do you draw a Bohr model?

Put electrons into energy levels around the nucleus.

What are valence electrons?

Electrons in the outermost energy level.

What is phosphorus's electron arrangement?

2, 8, 5.

How many valence electrons does phosphorus have?

5.

What happens when an electron falls from n=3 → n=2?

Energy is emitted as a photon.

What happens when an electron falls from n=5 → n=2?

Energy is emitted as a photon.

Which has more energy: n=3 → n=2 or n=5 → n=2?

n=5 → n=2.