Chemistry Leaving Cert Definitions

Front 1

Heisenberg's Uncertainty Principle

Back 1

States that it is impossible at one time to measure both velocity and the position of an atom

Front 2

Orbital

Back 2

An orbital is a region of space within which there is a high probability of finding an electron.

Front 3

Sublevel

Back 3

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

Front 4

Element

Back 4

An element is a substance that cannot be split into simpler substances by chemical means.

Front 5

Triad

Back 5

A triad is a group of three elements with similar chemical properties in which the atomic weight of the middle element is approximately equal to the average of the other two.

Front 6

Newlands' Octaves

Back 6

Newlands' Octaves are arrangements of elements in which the first and the eighth element, counting from a particular element, have similar properties.

Front 7

Mendeleev's Periodic Law

Back 7

When elements are arranged in order of increasing atomic weight, their properties recur periodically.

Front 8

Atomic Weight

Back 8

The atomic weight of an atom is the number of protons in the nucleus of that atom.

Front 9

Modern Periodic Law

Back 9

When elements are arranged in order of increasing atomic number, the properties of the elements recur periodically.

Front 10

Mass Number

Back 10

The mass number of an element is the number of protons and neutrons in the nucleus of an atom of that element.

Front 11

Isotopes

Back 11

Isotopes are atoms of the same element (they have the same atomic number) which have different mass numbers due to the different number of neutrons in the nucleus.