AP CHEM- STOICHIOMETRY

is a fundamental concept

in chemistry and physics that explains the

nature of matter in terms of atoms, the

smallest units of an element that retain the

properties of that element.

What is Basic Atomic Theory

The total number of protons and

neutrons in the nucleus.

mass number

The number of protons in the

nucleus of an atom, which

defines the element.

Atomic Number

average atomic mass

is the

weighted average of the atomic

masses of the naturally occurring

isotopes of an element. It

considers both the mass and the

relative abundance of each

isotope.

(relative abundance)(mass isotope #1) + (relative abundance)(isotope mass #2)

average atomic mass formula

relative abundance

refers to the percentage of that naturally occurring isotope found in nature

it measures mass better than any other technique-for isotopes of elements; gives information about chemical structures

what does a mass spectrometer do?

the presence and relative abundance of isotopes in a sample of an element. peaks—> appear at diff masses due to a diff number of neutrons in the nucleus of the isotope

what info can a mass spectrum tell us?