Final Exam Review

Final Exam Review 1.1

CHM 1.1

• Chm.1.1.1 Analyze the structure of atoms, isotopes, and ions.

• Chm.1.1.2 Analyze an atom in terms of the location of electrons.

• Chm.1.1.3 Explain the emission of electromagnetic radiation in spectral form in terms of the Bohr model. 

• Chm.1.1.4 Explain the process of radioactive decay by the use of nuclear equations and half-life. 

Chm.1.1.1 Analyze the structure of atoms, isotopes, and ions.

Atoms

Isotopes

Ions

Atoms

• Protons: 1 amu

• Neutrons: 1 amu

• Electrons: 1/2000 amu

Atomic # and Mass

Atomic Number Represented by "Z"

Atomic Mass Represented by "A"

Multiple Choice

the central region of an atom where its neutrons and protons are is its

• nucleus

• electron cloud

• core

• center

Isotopes

different forms of the same element that contain equal numbers of protons but different numbers of neutrons

X(element symbol) -- A (Mass Number)

Another way of writing isotopes

Average Atomic Mass vs Isotopic Mass vs Mass Number

AAM-the sum of the masses of its isotopes, each multiplied by its natural abundance

IM- mass of the most abundant isotope of an element

MN- the total number of protons and neutrons in a nucleus.

Multiple Choice

Four isotopes of lead include lead-204, lead-206, lead-207, and lead-208.  The average atomic mass of lead is 207.2.  Which isotope of lead is likely to be the most abundant.

• 204
• 206
• 207
• 208

Multiple Choice

In a correctly written symbol what would be located in the "A" position?

• number of neutrons
• atomic number
• number of electrons 
• mass number

Multiple Choice

How many neutrons does the isotope of lithium have?

• 8

• 3

• 4

• 5

Multiple Choice

If an atom has 10 protons, 10 neutrons, and 10 electrons, what is the mass of the atom?

• 10
• 20
• 30

Multiple Choice

What does the 1.00794 stand for?

• mass number

• atomic number

• average atomic mass

• number of protons

Average Atomic Mass

The average atomic mass of an element can be found on the periodic table, typically under the elemental symbol.

Average atomic mass = f₁M₁ + f₂M₂ 

f=fraction representing the natural abundance of the isotope

M= the mass number (weight) of the isotope.

Multiple Choice

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 9.012, Beryllium
• 12.011, Carbon
• 6.941, Lithium
• 10.812, Boron

Ions

an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Multiple Choice

Ions are: 

• atoms with a positive or negative charge
• atoms with no charge
• atoms with ONLY a positive charge
• atoms with ONLY a negative charge

Chm.1.1.2 Analyze an atom in terms of the location of electrons.

Bohr Model of the Hydrogen Atom

Electron Clouds

Bohr's Model of the Hydrogen Atoms

electrons can be moved into different orbits with the addition of energy

When the energy is removed, the electrons return back to their ground state, emitting a corresponding amount of energy – a quantum of light, or photon(quantum theory)

Electron Cloud Model

We can not know exactly where an electron is at any given time, but the electrons are more likely to be in specific areas.

Multiple Choice

Electron cloud is based on

• Quantum Mechanics
• Gold Foil Experiment
• Matter is made up of small particles called atoms
• Nuclear Theory

Chm.1.1.3 Explain the emission of electromagnetic radiation in spectral form in terms of the Bohr model. 

Quanta

Excited and Ground States

Emissions Spectrum

Bohrs Model of an Atom

An electron circles the nucleus only in fixed energy ranges called orbits.

 An electron can neither gain nor lose energy inside this orbit, but could move between orbits by absorbing or releasing a specific amount of energy. 

The lowest energy orbit is closest to the nucleus.

Quantum

Energy exists in discrete units called quanta.(the minimum amount of energy that can be absorbed or released by matter)

Ground State Vs Excited State

Ground State: the lowest possible energy that an atom can have

Excited State: energy level of an atom, ion, or molecule in which an electron is at a higher energy level than its ground state.

Multiple Choice

Light is emitted when an electron moves from the ________ state to the _________ state

• excited, ground
• ground, excited

Multiple Choice

Ground state means that an electron is...

• at its lowest possible potential energy

• in the first shell of an atom

• laying low for the weekend

• removed from an atom

Multiple Choice

Ground state means that an electron is...

• at its lowest possible potential energy

• in the first shell of an atom

• laying low for the weekend

• removed from an atom

Emissions Spectrum

When the electron moves to a lower energy level, it releases the energy difference in the two levels as electromagnetic radiation

Electromagnetic Radiation

this electromagnetic radiation is given off as photons(a particle representing a quantum of light).

Look at your Chem Reference Tables