Final Exam Review

Atoms

Isotopes

Ions

Atomic Number Represented by "Z"

Atomic Mass Represented by "A"

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

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.

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.

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

Bohr Model of the Hydrogen Atom

Electron Clouds

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)

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

Quanta

Excited and Ground States

Emissions Spectrum

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.

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

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.

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

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

Look at your Chem Reference Tables