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BIOCHEM Lesson 1
Atomic Structure
Question | Answer |
---|---|
Greek Philosopher who suggested that the world was made of two things - empty space and “atomos” | Democritus (460 BC) |
Greek word for uncuttable | Atomos |
2 main ideas of Democritus: | - Atoms are the smallest possible particle of matter/ - There are different types of atoms for each material |
John Dalton's Atomic Theory (1804) | 1. All matter is made of atoms. 2. Atoms of one element are all the same. 3. Atoms cannot be broken down into smaller parts. 4. Compounds form by combining atoms. |
Dalton's Early Atomic Model | “Billiard Ball” model - atoms as solid, hard spheres |
- discovered the electron - first scientist to show the atom was made of even smaller things | J.J Thomson (1897) |
What atomic model did J.J Thomson use? | "Plum Pudding" Model - a spherical cloud of positive charge, contained negative electrons |
- he discovered the nucleus of a gold atom | Ernest Rutherford (1913) |
What atomic experiment did Ernest Rutherford use? | Gold Foil experiment |
What was Rutherford's conclusion when a few alpha particles were deflected from the gold foil? | - The atom is mostly empty space. - There is a small, dense center with a positive charge. - discovered the nucleus in atoms |
smallest particle of an element that can exist alone | Atom |
it is the center region of the atom, made up of protons and neutrons | Nucleus |
Area surrounding nucleus containing electrons | Electron “cloud” |
Approximate mass of a proton or a neutron | amu |
Positive charge, 1 atomic mass unit (amu); found in the nucleus | Proton |
Neutral charge , 1 amu; found in the nucleus | Neutron |
Negative charge, mass is VERY small | Electron |
This describes the number of protons in the nucleus and determines the identity of the element | Atomic Number |
Number of protons + neutrons - Units are g/mol | Mass Number (Atomic Mass) |
Atoms of the same element with varying numbers of neutrons | Isotopes |