Evolution of Atomic Models and Structure of Atoms

Dalton's Model

Atoms are indivisible particles forming substances.

Thomson's Experiment

Identified electrons using cathode-ray tube.

Plum-Pudding Model

Electrons scattered in positive material.

Rutherford's Gold Foil Experiment

Discovered nucleus by deflecting alpha particles.

Nucleus

Central region containing protons and neutrons.

Proton

Positively charged particle in the nucleus.

Neutron

Neutral particle in the nucleus.

Electron

Negatively charged particle orbiting nucleus.

Atomic Number

Number of protons in an atom.

Mass Number

Total of protons and neutrons in nucleus.

Isotopes

Atoms with same protons, different neutrons.

Relative Atomic Mass

Average mass of isotopes based on abundance.

Mendeleev's Periodic Table

Elements arranged by atomic mass and properties.

Groups in Periodic Table

Columns of elements with similar properties.

Periods in Periodic Table

Rows indicating increasing atomic number.

Metal

Element forming positive ions, left of table.

Non-metal

Element not forming positive ions, right of table.

Electronic Configuration

Distribution of electrons in atomic shells.

Charge of Proton

+1, contributes to atomic charge.

Charge of Neutron

0, does not affect atomic charge.

Charge of Electron

-1, balances charge of protons.

Atomic Stability

Atoms are neutral due to equal protons and electrons.

Rutherford's Model

Atom is mostly empty space with nucleus.

Calculating Neutrons

Mass number - atomic number equals neutrons.

Mendeleev's Predictions

Gaps in table predicted undiscovered elements.

Relative Abundance of Isotopes

Affects average atomic mass calculations.

Electronic Shells

Layers around nucleus containing electrons.

Chlorine Isotopes

Chlorine-35 and Chlorine-37 in specific proportions.