Subatomic Particles

Atom

the mallet unit of an element that retains the properties of that element

has a nuetral charge IF the protons and electrons equal the same

Nucleus

-smallest part of an atom

-makes up most of the mass

-made up of protons and neutrons

-positively charged

Protons

positive charge

1 AMU

determines the type of element

in the nucleus

determines the atomic number

neutron

neutral charge

in nucleus

1 AMU

AMU(atomic mass unit)

used instead of grams

one amu =1/12 of the mass of the carbon-12 atom

Electron

negatively charged

in the electron cloud

makes up most of the volume in an atom

0 AMU

if the atom is neutral the number will be the same as the proton

Hyphen notation

Full name of element-mass #

charge of an element

+ or - depending on balance of electrons and protons

Elements symbol

variable representing the element

-identifies the name of element AND mass

atomic mass

how many protons+neutrons in the nucleus

-identified the name of element AND mass

shows the average mass for that element

Isotope

atoms with the same number of protons but a different number of neutrons

• differ in number of neutrons so they also differ in MASS

• when finding average atomic mass must use a weighted average because different isotopes of an element are found in different amounts

Average atomic mass

Weighted average mass of the isotopes of an element

Calculating Average Atomic Mass

• convert percent abundance—> to decimal abundance by dividing it by 100

• multiply the decimal abundance by the mass of the ISOTOPE

• add together the mass contribution(AMU) of each isotope and roundup to determine the atomic mass