The Periodic Table Flashcards
What is an element?
An element is a substance that cannot be split into simpler substances by chemical means
What is a triad?
A triad is a group of three elements with similar chemical properties in which the atomic weight (relative atomic mass) of the middle element is approximately equal to the average of the other two
What is Newland’s Octaves?
Newland’s Octaves are arrangements of elements in which the first and the eight element, counting from a particular element, have similar properties
What is Mendeleev’s Periodic Law?
3
When elements are arranged in order of increasing atomic weight (relative atomic mass),
The properties of the elements recur periodically,
i.e. the properties displayed by an element are repeated at regular intervals in other elements
What is the atomic number of an atom?
The number of protons in the nucleus of that atom
What is the modern periodic table?
An arrangement of elements in order of increasing atomic number
What is modern periodic law?
3
When elements are arranged in order of increasing atomic number
The properties of the elements recur periodically,
i.e. the properties displayed by an element are repeated at regular intervals in other elements
What is the mass number of an element?
The mass number of an element is the sum of the number of protons and neutrons in the nucleus of an atom of that element
What are isotopes?
4
Isotopes are atoms of the same element
(i.e. they have the same atomic number)
which have different mass numbers
Due to the different number of neutrons in the nucleus
Define relative atomic mass.
4
The average of the mass numbers of the isotopes of the element
As they occur naturally
Taking their abundances into account and
Expressed on a scale in which the atoms of the carbon-12 isotope have a mass of exactly 12 units
What is the principle of mass spectrometry?
Charged particles moving in a magnetic field are deflected to different extents according to their masses and are thus separated according to these masses
What is electron configuration?
The electron configuration shows the arrangement of electrons in an atom of an element
What is the Aufbau Principle?
When building up the electron configuration of an atom in it’s ground state, the electrons occupy the lowest available energy levels
What does Hund’s Rule of Maximum Multiplicity state?
2
It states that when two or more orbitals of equal energy are available,
The electrons occupy them singly before filling them in pairs
What does the Pauli Exclusion Principle state?
That no more than two electrons may occupy an orbital and they must have opposite spin
