atoms and the periodic table
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what makes up everything?
atoms
electron charge
-1
proton charge
+1
neutron charge
0
electron mass
1/1836
proton mass
1
neutron mass
1
what is the most concentrated part of the atom?
nucleus
atomic number
number of protons or electrons
atomic mass
number of protons + neutrons
what is the overall charge of an atom?
0
why has the atom got an overall charge of 0?
for every proton an atom has, it has the same number of electrons. therefore, they cancel each other out.
what is the shell also known as?
energy level
which shell has the lowest energy level?
the shell closest to the nucleush
how many electrons can the first shell hold?
2
how many electrons can the second and third shell hold?
8
what are the columns in the periodic table called?
groups
what are the rows in the periodic table called?
periods
what is group 1 known as?
alkali metals
what is group 7 known as?
halogens
what is group 0 known as?
noble gases
what is an isotope?
atoms with the same atomic number but different atomic masses. they have different amounts of neutrons.
what is relative atomic mass?
average mass of all isotopes abundance of that element
ram formula
((% x mass) + (% x mass))/100