1&2) Key Concepts in Chemistry A Flashcards
how has the Dalton method changed over time?
-discovery of subatomic particles…. electrons
what is the structure of an atom?
- nucleus with protons+neutrons
- electrons surrounding in electron shells
what is the relative mass and relative charge of a proton?
- RC- +1(positive)
- RM- 1
what is the relative mass and relative charge of a neutron?
- RC-0(no charge)
- RM- 1
what is the relative mass and relative charge electron?
- RC- -1(negative)
- RM- 1/1835 (negligible
why do atoms contain equal numbers of electrons and protons?
- no overall charge
- charges cancel out
how big is the atoms nucleus compared to the whole thing?
-nucleus can be 100,000 smaller diameter
where is most of the mass in an atom?
-in the nucleus
what is the mass number of an atom? where is it found?
- protons+neutrons
- top number
what is the atomic number?where is it found?
- protons only
- bottom number
what is an isotope?
- same element
- same atomic number
- different mass number
if you have the mass number and atomic number how do you work out how many protons, neutrons and electrons there are?
atomic number= -number of protons
-same number of electrons
mass number= neutrons+protons
what are relative atomic masses compared to?
-carbon-12
how does the existence of isotope result in not having whole number relative atomic masses?
- takes into account all of the isotopes
- amount of each isotope
how do you work out the relative atomic mass?
and what is the symbol for RAM?
number of atoms
-Ar