Concept 1: Intro to Electrons

Electrons are primarily known for (a)   in chemistry.

• Being the heaviest subatomic partic

• Acting like protons and neutrons

• Behaving like waves

• Having no energy

Answer explanation

Electrons are known for their wave-like behavior, which is a fundamental concept in quantum mechanics. This wave-particle duality is crucial in understanding chemical bonding and reactions, making 'behaving like waves' the correct choice.

Tags

NGSS.HS-PS4-3

Why aren't electrons pulled into the nucleus due to electromagnetic force?

• They have no charge

• They have insane amounts of energy

• They are repelled by protons

• They are too large

Answer explanation

Electrons are not pulled into the nucleus because they possess significant energy, allowing them to occupy stable orbits. This energy counteracts the electromagnetic attraction to protons, preventing them from collapsing into the nucleus.

Tags

NGSS.HS-PS2-4

Match the following types of energy with their effects on electrons.

• Energy involved in nuclear reactions

• Mechanical energy

• Energy involved in chemical reactions

• Chemical energy

• Energy that can excite electrons

• Radiant/light energy

• Energy associated with motion

• Nuclear energy

Tags

NGSS.HS-PS4-3

What is electromagnetic radiation?

• A form of energy that behaves like particles

• A form of energy that exhibits wavelike behavior

• A form of energy that is stationary

• A form of energy that only travels through solids

Answer explanation

Electromagnetic radiation is a form of energy that exhibits wavelike behavior, such as light and radio waves. This distinguishes it from stationary energy and energy that only travels through solids.

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-4

Match the following phenomena with their types of waves.

• Water surface waves

• Ocean waves

• Acoustic waves

• Earthquakes

• Electromagnetic radiation

• Radio waves

• Seismic waves

• Sound waves

What is the speed of light in a vacuum?

• 3.0 x 10^6 m/s

• 3.0 x 10^8 m/s

• 3.0 x 10^10 m/s

• 3.0 x 10^12 m/s

Answer explanation

The speed of light in a vacuum is a fundamental constant in physics, measured as approximately 3.0 x 10^8 m/s. This value is crucial for understanding electromagnetic radiation and the theory of relativity.

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3

Which of the following relationships is true for wavelength (λ) and frequency (ν)?

• As λ increases, ν increases

• As λ decreases, ν decreases

• As λ increases, ν decreases

• λ and ν have no relationship

Answer explanation

Wavelength (λ) and frequency (ν) are inversely related, as described by the equation c = λν, where c is the speed of light. Therefore, as λ increases, ν decreases, making 'As λ increases, ν decreases' the correct choice.

Tags

NGSS.HS-PS4-1

What is the unit of frequency (ν) in the context of electromagnetic waves?

• Meters (m)

• Seconds (s)

• Hertz (Hz)

• Joules (J)

Answer explanation

The unit of frequency (ν) for electromagnetic waves is Hertz (Hz), which measures cycles per second. Other options like meters, seconds, and joules represent different physical quantities, not frequency.

Tags

NGSS.HS-PS4-1

The velocity of a wave is calculated as velocity = λ (a)   ν

• velocity = λ + ν

• velocity = λ / ν

• velocity = λ x ν

• velocity = λ - ν

Answer explanation

The velocity of a wave is calculated using the formula velocity = λ x ν, where λ is the wavelength and ν is the frequency. This means the correct relationship involves multiplication, making 'velocity = λ x ν' the right choice.

Tags

NGSS.HS-PS4-1

What happens to electrons when they absorb energy?

• They drop to a lower energy level.

• They remain in the ground state.

• They jump to a higher energy level.

• They emit light immediately.

Answer explanation

When electrons absorb energy, they gain enough energy to move from a lower energy level to a higher energy level, a process known as excitation. Therefore, the correct answer is that they jump to a higher energy level.