Chemistry Unit 2 Atom and Nuclear Chemistry

Name and describe the force that keeps the nucleus from breaking apart

Strong nuclear force, binds protons and neutrons together in the atomic nucleus

What did Ernest Rutherford discover about atoms?

The atomic nucleus and that it has a dense, positive center

What experiment did Ernest Rutherford conduct to discover that the atomic nucleus is dense and positive?

The gold-foil experiment.

What did J.J. Thompson discover about atoms?

Electrons and that they have a very small mass.

What experiment did J.J. Thompson conduct to investigate that atoms have small particles called electrons?

The Cathode Experiment

What experiment did J.J. Thompson conduct to confirm that electrons existed?

The Plum Pudding Model

What did John Dalton discover about the atom?

All matter is made of tiny, indestructible and invisible atoms.

What experiment did John Dalton conduct to discover the atom?

He experimented on gases and compounds.

How to calculate average atomic mass:

(abundance of A x 1/100) x amu of A plus (abundance of B x1/100) x amu of B = average atomic mass

Round with sig figs

Aufbau Principle

Electrons fill the lowest energy orbitals first.

Hund’s Rule

No double electrons before all other shells are filled.

Pauli Extension Principle

Each shell can hold two electrons with opposite spins.

Orbital Diagram:

The boxes

Electron configuration:

Managers code

Photon Energy equation:

E=hf (h=6.63 × 10^-34)

Coloumbic Attraction:

The force of attraction between protons and electrons: weakens as there are more protons present.

Ionization Energy

The amount of energy needed to remove an electron from an atom.

Electronegativity:

The ability of an atom’s nucleus to attract electrons from a different atom.

What experiment did Robert Milikan conduct to discover that electrons have a negative charge?

The Oil-Drop experiment

What did Robert Milikan discover about the electron?

That electrons have a strong negative charge.