CHEMISTRY CH4

Question 0

Henry Becquerel – discovered __________ . He tested various minerals to see what emitted ________, specifically
_____. He found that radioactive elements _______ (gave off invisible rays) when exposed to photographic film.

Answer 0

Radioactivity
Radiation
Uranium
fluoresced

Question 1

Rutherford along with Bohr, concluded that the atom

was mostly __________. ( _________ experiment)

Answer 1

empty space with a dense central core called the nucleus

Gold foil

Question 2

Pierre and Marie Curie – continued ________ work with uranium and discovered the elements responsible for
radiation given off by uranium.

Marie discovered ______ and _______ (1 million times more radioactive than uranium). She determined this mysterious form of energy which enabled radioactivity to penetrate other materials
was not a chemical process, it is ______.

tell how Pierre died

Answer 2

Becquerels

Polonium
Radium

Atomic in nature

Traffic collision

Question 3

Rutherford discovered _______, _______, _________

Answer 3

Alpha
Bata particles
Gamma rays

Question 4

Radioactivity is the

Answer 4

spontaneous production of rays from unstable atomic nuclei.

Question 5

Atoms can gain stability by ______ (emitting radiation).

Atomic stability is determined primarily by the ratio of the number of
_______ to the number of _______.

atoms containing either too many or too few neutrons are _______

When the ratio of protons to neutrons in the nucleus of the atom is not balanced the unstable nucleus will decay giving off _____

Answer 5

Losing energy

Neutrons
Protons

Unstable

Alpha and/or Beta particles

Question 6

Radioactive decay occurs by releasing ______

Answer 6

particles and energy

Question 7

Benefits of radioactivity:

And radioisotopes:

Answer 7

A: X-rays, tumor therapy, smoke detectors

I: prevents cancer from spreading