ibc

Electron Basics:

What are electrons?

The subatomic particles that have a negative charge

WHERE are electrons?

In shells or energy levels that sorround the nucleus of the atom

Bohr Models:

What do they show?

Negative electrons circling the positive electrons at fixed positions from the nucleus

What do they look like? 

Can you draw a Bohr Model of a given element?

Quantum Mechanical Model:

Who was Erwin Schrödinger and what was his theory?

Thought the problem with Bohr’s model was that it was restricting the electrons in specific orbits. He believed they travelled in waves.

What are orbitals?

The region around the nucleus where electrons are most likely to be.

What is the Quantum Mechanical Model?

Each orbital around the nucleus resembles a fuzzy cloud. The densest area of the cloud is where electrons have the greatest chance of being.

The Electron Cloud:

What is the Electron Cloud?

The location of the electrons in the quantum mechanical cloud model.

What are energy levels?

Fixed distances from the nucleus where electrons can be found.

What are Valence Electrons?

Electrons in the outermost energy level of an atom.

What are the principal energy levels and how are they like a parking garage?

On each level are parking spots for the electron. The orbitals are the parking lots.

What are the four orbital (sublevel) types?

S, p, d, f.

What are the 4 orbital shapes and how many electrons can each hold?

Sphere- 2, peanut-6, dumbbell-10, flower-14

Rules for Electron Locations in the Cloud:

Know what each of these rules state and why they help us determine where electrons are in the cloud:

Aufbau Principle

Each electron occupies the lowest energy level

Pauli Exclusion

Two electrons can occupy a single orbital but only if they have opposite spins.

Hund’s Rules

Single electrons with the same spin must occupy each energy level before additional electrons can occupy the same one.

Can you complete an Orbital Filling Diagram for a given element?

Electron Configuration

What is electron configuration?

The arrangement of electrons in teh atom

Can you write long-hand and short-hand (noble gas) configurations for given elements?

What is the Octet Rule?

Atoms are most stable when they have 8 electrons in their outermost shell

What are Lewis Dot Structures?

Show only the valence of elements

Electromagnetic Waves

What is an electromagnetic wave?

Transfer energy through matter or across space

Define electromagnetic radiation.

Transfer energy through electromagnetic waves.

How does an electromagnetic wave begin? 

When an Electrically charged particle vibrates. This causes a vibrating magnetic field, which in turn causes a vibrating electric field.

What happens when electromagnetic waves strike matter?

They may be reflected, deflected, or diffracted.

What are some sources of electromagnetic waves on Earth?

The sun, radio waves, microwaves, x-rays

What is the speed of light across space?

2.998 x 10^8 / 3.00 x 10^8 m/s

Radio waves:

Where are radio waves on the electromagnetic spectrum?

The beginning of it.

Compare and contrast AM and FM radio broadcasts.

Amplitude or frequency of the waves.

Microwaves:

What are microwaves?

Relatively long wavelengths, low frequencies, least amount of energy

Identify uses of microwaves.

Used microwave, ovens, cell phones and radar

How does a cell phone use microwaves to encode and transmit sounds?

Changing the frequency of the rays. The microwaves then travel through air to the cellphone tower and eventually to the receiver.

What does radar stand for? How does radar work?

Radio detection and ranging. The use of reflected microwaves.

Light:

Relate sunlight to the electromagnetic spectrum. Where do the waves that are commonly called light fall on the spectrum?

Infrared light, visible light, ultraviolet

Define infrared light. How can infrared light be detected?

Light with the longest wavelength and lowest frequency. You can’t see it, but feel it has heat.

What is visible light? What determines the color of visible light?

Very narrow range of wavelengths that only humans can see. different wavelengths.

Describe ultraviolet light. How and why should you protect your skin from ultraviolet light?

Has shorter wavelengths and higher frequencies than visible light, and can kill germs. It can damage cells and cause cancer, so wear suncreen.

X-Rays:

What are X-rays? Where do they fall in the electromagnetic spectrum?

High frequency, more energy. Before gamma rays.

How are X-rays used?

To make images of bones and teeth inside your body and see luggage in the airport.

Why are X-rays dangerous?

They can damage cells and cause cancer.

Gamma Rays:

Describe the wavelength, frequency, and energy of gamma rays.

Short wavelength, high frequency, more energy.

What are some sources of gamma rays?

Radioactive atoms, nuclear explosions, stars

Identify how gamma rays can affect living things.

Gamma rays can destroy living cells, produce mutations, and cause cancer. 

Anatomy of a Wave:

What is a transverse wave?

A wave in which the particles of the medium distance the particles of the medium vibrate perpendicular to the direction the wave travels.

Define wave amplitude.

The maximum distance the particles of the medium move from their resting positions when a wave passes through.

How does the energy of a disturbance affect wave amplitude?

Disturbance caused when more energy has a greater amplitude.

What is the wavelength of a wave?

One way of measuring a wave.

Frequency/wavelength/Energy Calculations

What is wave frequency?

The number of waves that pass a fixed point in a given amount of time.

Can you calculate the Energy of a wave if given the frequency/wavelength?

Atomic Emission:

What happens when atoms/ions in the ground state are heated to high temperatures?

Some electrons may absorb enough energy to allow them to jump to higher energy levels. The element is then said to be in an excited state. This configuration is unstable and the electrons fall back to their normal positions of lower energy( ground state)

What happens once the heated electrons return to their normal levels?

The energy they absorb is emitted in the form of electromagnetic energy.

What are Spectral Lines? How can we use atomic spectra (spectral lines) to identify elements?

What are photons?

The balmer series of emission lines, electrons falling to the n=2 energy level, emit light in the visible range.

How can Spectroscopy help us analyze and identify an energy source?

What is a flame test?

It aims an energy source at a sample and measures the change in the energy source. A flame is used to identify the characteristics of the color produced by the flame when an unknown metallic ion reacts with it.