Discoveries
Structure of Atoms
Isotopes
Radioactivity
Types of Decay
100

Believed that all particles are made of wind, water, fire, and Earth

Who is Aristotle?

100

Dense, neutrally charged mass in the center of an atom

What is the nucleus?

100

The part of the atom in isotopes that are the same. 

What are the protons?

100

The cause of radioactivity

What is nuclear decay?

100

This becomes unstable, causing decay.

What is the nucleus?

200

Discovered the nucleus using the Gold Foil experiment

Who is Rutherford?

200

Positively charged particles that are also equal to the atomic number

What is the proton?

200

The most common occurring form of carbon

C 12

200

This changes in an element and causes radioactivity

What are number of protons?

200

This particle is made of two protons and two neutrons

What is an alpha particle?

300

Believed that atoms traveled around nucleus in orbits

Who is Bohr?

300

The part of the atom that makes up most of it's mass

What is the nucleus? 

300

The part of the atom that is DIFFERENT among the same element's isotopes

What are the neutrons?

300

Where radiation is released in the nucleus. 

What is the nuclei?

300

This occurs when a neutron atom changes into a proton?

What is beta decay?

400

First proposed the structure of the atom

Who is Democritus?

400

Negatively charged particles that orbit around the nucleus

What is electrons? 

400

When written, the element's name is followed by this

What is the mass number? 

400

The two scientists that accidentally discovered radioactivity

Who are Becquerel and Curie?

400

The types of ray that does not contain particles, but has high energy.

What are gamma rays?

500

Discovered the neutron

Who is Chadwick?

500

The currently accepted atomic theory

What is the electron cloud?

500

This is added to find the mass of the atom

What is the number of protons and neutrons?

500

Scientists discovered that elements can spontaneously change into new elements when they tried to convert lead into this element.

What is gold?

500

The two types of decay that result in new elements

What is alpha and beta decay?

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