science unit two test

Democritus beliefs?

Answer explanation

introduced the idea of atoms and how they made matter, thought different atoms existed for every type of matter

Lavoisier findings?

Answer explanation

showed that wood and oxygen have the same mass after burning as ash, water, and CO2. developed Law of conservation of energy.

What are John Dalton's findings?

Answer explanation

Atomic model (set of ideas), matter was made of atoms too small to be seen by human eye, each type of matter is made up of one type of atom.

What was JJ Thompsons experiment?

Answer explanation

Cathode Ray Experiment, with a glass tube sealed at both ends with most air pumped out. Metal plates at each end: cathode plate=negative, anode plate=positive. Ray was sent through attracting positive anode.

What was JJ Thompson's outcome of his experiment?

Answer explanation

since rays travelled to positive anode, he found cathode ray was made up of negative particles. found that opposites attract. also found invisible, negatively charged particles called electrons

Ernest Rutherford Experiment?

Answer explanation

Alpha Particle Experiment, had bombarded gold foil with alpha particles (positive charge) which were predicted to pass through foil, some particles bounced back, some traveled through.

Ernest Rutherford experiment outcome?

Answer explanation

particles that bounced back from foil showed positive particles were in center, particles that traveled through showed the atom was made of mostly empty space.

Ernest Rutherford's Atomic Model?

Answer explanation

Determined that atoms must be made of mostly empty space, named two parts of atom: nucleus and protons

what did Niels Bohr discover?

Answer explanation

The Modern Atomic Model

What does the Modern Atomic Model state?

Answer explanation

found that electrons in the atom are arranged by energy level, lower energy levels closest to nucleus, higher energy levels further away from nucleus, determined electrons move in an electrons cloud around the nucleus