Atomic Chemistry Flashcards
(24 cards)
What is Dalton’s Atomic Theory?
It states that matter cannot be created or destroyed but simply converted from one form to another.
What does the Law of Conservation of Mass state?
Matter cannot be created or destroyed, only converted from one form to another.
How many particles are in one mole of a substance?
One mole of a substance contains 6 x 10^23 particles of that substance.
What is an energy level ‘n’?
An energy level ‘n’ is defined as the fixed energy value that an electron may have.
What is the ground state of an atom?
The ground state of an atom is the one in which the electrons occupy the lowest available energy level.
What is an excited state of an atom?
An excited state of an atom is one in which the electrons occupy higher energy levels than those available in the ground state.
What is an orbit in atomic chemistry?
An orbit is the fixed path that an electron takes around the nucleus.
What is a continuous spectrum?
When white light (from an ordinary light bulb) is passed through a prism, a continuous spectrum is observed.
What is an emission line spectrum?
When light from a discharge tube (e.g., hydrogen or mercury) is passed through a prism, the spectrum observed consists of narrow, coloured lines.
What is an absorption spectrum?
When white light passes through a gaseous sample of an element and then a prism, it absorbs wavelengths of light identical to those it emits when excited, appearing as dark lines in the spectrum.
What is a sublevel?
A sublevel is a subdivision of a main energy level and consists of one or more orbitals of the same energy.
What is Heisenberg’s Uncertainty Principle?
It states that it is impossible to measure at the same time both the velocity and position of the electron.
What is an orbital?
An orbital is a region in space around the nucleus of an atom where there is a high probability of finding an electron.
What is the Aufbau Principle?
When building up electron configuration of an atom in its ground state, the electrons occupy the lowest energy level available.
What is Hund’s Rule of Maximum Multiplicity?
When two or more orbitals of equal energy are available, the electrons occupy them singly before filling in pairs.
What does Pauli’s Exclusion Principle state?
No more than two electrons may occupy the same orbital and they must have opposite spins.
What is the mass number of an element?
It is the sum of the number of protons and neutrons in the nucleus of an atom of that element.
What is electron configuration?
The electron configuration shows the arrangement of electrons in an atom of an element.
What is an element?
An element is a substance that cannot be split into simpler substances by chemical means.
What is a triad in chemistry?
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.
What is the Law of Octaves?
Arrangements of elements in order of increasing atomic weight where the first and eighth element of each group have similar properties.
What is Mendeleev’s Periodic Law?
Periodic recurrence of properties when elements are arranged in order of increasing atomic weight.
What is the Modern Periodic Law (Moseley)?
When elements are arranged in order of increasing atomic number, the properties of the elements recur periodically.
What are Cathode Rays?
Cathode Rays are streams of negatively charged particles called electrons. They travel in straight lines from the cathode to the anode and are deflected by electrical and magnetic fields, and have sufficient energy to move a small object such as a paddle wheel.
