module 3 Flashcards
memorize
who coined the word atomos?
Democritus
the scientist who provided precise and detailed description of the building blocks of matter
John Dalton
elements that combine in ratios of simple whole numbers to form a compound
law of definite proportions or constant composition
when two elements react to form two or more different compounds
law of multiple proportions
states that matter is neither created nor destroyed
law of conservation of mass
negatively charged subatomic particle
electron
who discovered electrons?
J.J. Thomson
who was behind the cathode ray tube experiment?
J.J. Thomson
positively charged subatomic particle
proton
who discovered protons?
Ernest Rutherford
located at the center of atom
nucleus
who was behind the famous gold foil experiment?
Ernest Rutherford
neutral subatomic particle
neutron
who discovered neutrons?
James Chadwick
who was behind the beryllium foil experiment?
James Chadwick
equal to the number of protons in an atom
atomic number
total amount of particles
mass number
same number of protons, but different number of neutrons
isotopes
isotopes that do not undergo radioactivity
stable isotopes
isotopes that exhibit radioactivity
unstable isotopes
an atom may either lose or gain an electron to give an electrically charged species called
ions
when an atom gains an electron, it becomes negatively charge and is then called an
anion
when an atom gives off an electron, its charge become positive and is then called a
cation
collection of two or more atoms held in specific arrangement due to sharing of electrons and acts a single unit is called a
molecule
