atom and the periodic table Flashcards
(16 cards)
name the scientist from oldest to newest discovery of an atom
Thomson, Geiger, Rutherford, Bohr, Chadwick
what did Thomson discover
discovered electrons and representation of an atom and invented plum pudding model
Describe the plum pudding model of an atom
negative electrons surrounded by a sea of positive charge
what was Geiger’s experiment
bombarded a thin sheet of gold with alpha particles although most positively charged alpha particles passed through atoms, tiny number deflected back
What was Rutherford’s discovery
discovered nuclear model - positive charge must be concentrated in the nucleus
what was bohr’s discovery
electrons must orbit the nucleus
what was chadwick’s discovery
provided evidence of neutrons within the nucleus
what are the 3 subatomic particles
protons, neutrons and electrons
why do atoms have no overall charge
they contain the same number of protons and electrons
what is the relative charge of protons, neutrons electrons
protons: +1
neutrons : 0
electrons: -1
what is the relative mass of protons neutrons and electrons
protons: 1
neutrons:1
electrons: very small
what does the atomic mass show
total number of protons and neutrons
what does the atomic number show
number of protons electrons
what does the number of neutrons equal
mass number - atomic number
what is an isotope
elements with the same number of protons but different number of neutrons
- same atomic number different mass number
what are ions are how do they form
ions are charged particles. They’re formed when atoms loose electrons (positively ions) or gain (negative ions) electrons
