chemistry
What are the numbers on the top of the periodic table called?
group numbers
What are the numbers on the side of the periodic table called?
period numbers
what is the maximum arrangement of an atom's shells until atomic number 20
2.8.8.2
What did Ernest Rutherford discover?
protons in the neucleus
What did J.J. thompson describe his model as
plum pudding model
what did jj tomphson discover
electrons
what did niels bohr suggest
electrons move in shells
what did james chadwick discover
neutrons
Out of these groups of atoms, which react aggressively: Halogens, Noble gas, Alkalis
Halogens, Alkalis
what is the relative mass of a proton + a neutron + an electron in AMU
2 AMU, as an electron's mass is negligible
What is mass number?
number of protons + number of neutrons
how can you tell how many electrons there are in an atom?
atomic number = proton number = electron number
what are rings of electrons called?
shells