Chem - atomic models

Law of Conservation of Mass

Mass of reactants = mass of products.

Law of Conservation of Mass (reactions)

Matter is rearranged, not created or destroyed.

Law of Definite Proportions

A compound always contains the same elements in the same mass ratio.

Law of Multiple Proportions

Two elements can form different compounds using small whole

Dalton's Atomic Model

Atoms are tiny, indivisible solid spheres.

Dalton's Theory

All matter is made of atoms.

J.J. Thomson

Discovered the negatively charged electron.

Cathode Ray Tube

Used electric and magnetic fields to discover the electron.

Plum Pudding Model

Negative electrons embedded in a positively charged sphere.

Ernest Rutherford

Discovered that atoms have a small, dense, positive nucleus.

Gold Foil Experiment

Showed that atoms are mostly empty space.

Rutherford's Planetary Model

Electrons orbit a small, dense, positive nucleus.

Neils Bohr

Proposed that electrons occupy specific energy levels.

Bohr's Model

Electrons orbit the nucleus in defined energy levels.

Ground State

Electrons are in their lowest available energy levels.

Excited State

Electrons have moved to higher energy levels.

Electron Returning to Lower Energy Level

Releases energy as electromagnetic radiation.

Wave Mechanical Model

Electrons behave like waves and occupy regions of probability around the nucleus.

Modern Atomic Model

Atoms are mostly empty space with a small, positive nucleus and surrounding electrons.

Energy Levels

Main electron energy levels, represented by integers (1, 2, 3, etc.).

Maximum Electrons in an Energy Level

2n².

Sublevels

Sections within energy levels labeled s, p, d, and f.

First Energy Level

1s.

Second Energy Level

2s, 2p.

Third Energy Level

3s, 3p, 3d.

Orbitals

Regions where electrons are most likely found.

Maximum Electrons in One Orbital

2 electrons.

s Sublevel

1 orbital; 2 electrons maximum.

p Sublevel

3 orbitals; 6 electrons maximum.

d Sublevel

5 orbitals; 10 electrons maximum.

f Sublevel

7 orbitals; 14 electrons maximum.