chapter 4.2 Flashcards
who named atoms
democritus
who developed atomic theory (tiny particles)
dalton
opposite charges…
attract
in the cathode ray experiment, the particles in the beam had which charge
negative e-
what is the charge of an atom
neutral
what was JJ thomson’s model?
plum pudding
who discovered alpha particles and protons
Ernest rutherford
what is an alpha particle
fast-moving positively charged particles
who discovered the neutron
james chadwick
who discovered the electron
thomson
what is atomic number? what does it also equal?
number of protons in an atom; electrons
mass number
number of protons and neutrons in the nucleus
equation to find number of neutrons?
mass number - atomic number
isotopes have the same number of _________ but a different number of ________
same atoms; different mass
what happens when atoms absorb energy?
an increase in kinetic energy, phase change, and energy is absorbed
what causes e- to move to a higher/lower energy level?
when the atom gains/loses energy
what is an electron cloud
visual model of the most likely locations for electrons in an atom
what is an orbital
a region of space around the nucleus where an electron is likely to be found
what is ground state
a state in which all the electrons in an atom have the lowest possible energies
what are all the same number in subatomic particles?
proneutonic number
