Question | Answer |
What is the Theory of the 4 Essences? | All forms of matter were a combination of earth, air, fire, and water.
Many Greeks believed this. |
Who was the Greek Philosopher who believed in the Theory of the 4 Essences? | Aristotle |
Who was the scientist who opposed the Theory of 4 Essences, and came up with the idea of an "atom"? | Democritus |
What were Alchemists? | Scientists of the Middle Ages
Tried to change cheap metals into gold
Tried to stop aging
Tried to cure diseases |
When two or more elements combine to form a new substance, what is this known as? | A compound |
What are some examples of common compounds | Water
salt
sugar
rust
tarnish
ammonia |
Who was John Dalton? | An English school teacher who proved Democritus was correct.
He proposed his own Atomic Theory. |
What is John Dalton known as? | the "Father of the Modern Day Atomic Theory" |
Who was Marie Curie? | A Polish-born Scientist
Worked most of her life with her husband, Pierre
They studied radioactive elements |
What were the two elements Marie Curie and Pierre discovered? | Radium and Polonium |
Who was Ernest Rutherford? | A British physicist
1911 discovered that atoms are mainly empty space |
What did Ernest Rutherford discover in 1918? | The proton |
Who was Niels Bohr? | A scientist who initially believed that electrons flew around the nucleus in orbits |
What was Niels Bohr's changed idea? | Electrons were forced on shells (orbitals) outside of the nucleus.
He believed electrons could "jump" from one shell to another. |
What is an element's atomic number? | The number of protons and neutrons in the nucleus of the atom.
The atomic mass is the total number of nucleons in an atom. |
What is the atomic mass of an element equal to? | The number of protons and neutrons in the nucleus of the atom. |
What is atomic mass? | The total number of nucleons in an atom. |
How do you determine the number of neutrons in an atom's nucleus? | Subtract the atomic number from the atomic mass |
How many known elements are existing? | 118 |
How many elements can be found in nature? | 94 |
Why can the number of protons and electrons in an element be the same? | Since protons have a positive charge and the electrons have a negative charge, the overall charge of an atom is normally neutral |
What does Fermium have an atomic number of? Mass? How many neutrons are in the nucleus of an atom of fermium | Atomic number- 100
Mass- 257
Neutrons- 157 |