Chapter 3.2-4.10: Arrangement of Electrons in the Atom & Trends in the Periodic Table

Energy level

The fixed energy value that an electron in an atom may have

Ground state of an atom

When electrons occupy the lowest available energy levels

Excited state of an atom

When electrons occupy higher energy levels than those available in the ground state

Heisenberg's Uncertainty Principle

It is impossible to measure at the same time both the velocity and position of an electron

Hund’s Rule

The Pauli Exclusion Principle

Aufbau Principle

Electrons always occupy the lowest available energy level first.

first ionisation energy

the minimum amount of energy required to remove an electron from the outermost energy level

second ionisation energy

An orbital

A region in space within which there is a high probability of finding an electron

A sublevel

A subdivision of a main energy level and consists of one or more orbitals of the same energy

an element

A substance that cannot be broken down into simpler substances by chemical means

electron configuration

the arrangement of electrons in an atom of that element

atomic radius

electronegativity