Terms in Chem Flashcards
Relative atomic mass (Ar)
the weighted average mass of naturally occurring atoms of an element on a scale where an atom of carbon-12 has a mass of exactly 12 units
Relative isotopic mass
the mass of a particular atom of a particular isotope of an element on a scale where an atom of carbon-12 has a mass of exactly 12 units
Relative molecular mass (Mr)
the relative mass of one molecule of the compound on a scale where the carbon-12 isotope has a mass of exactly 12 units
Relative formula mass (Mr)
the mass of 1 formula unit of a compound measured on a scale on which an atom of the carbon-12 isotope has a mass of exactly 12 units
Avogadro constant (Na or L) and number
The number of atoms, molecules, ions or other entities in one mole of a substance. The Avogadro constant is equal to 6.02 x 10^23
mole
the amount of a substance that has the same number of specific particles (atoms, molecules, or ions) as there are atoms in exactly 12 g of the carbon-12 isotope
Molar mass
the mass of a mole of a substance
Avogadro’s constant
the number of atoms in a mole of atoms (6.02 x 10^23 atoms)
Isotope
atoms of the same element (same number of protons) with different numbers of neutrons
Molecular formula
A formula which shows the number of atoms of each element in a molecule
Anhydrous
Anhydrous salts are the compounds left after removing the water from a hydrated salt. Anhydrous means ‘without water’
Hydrated
Contains water
Acid
A Proton Donor
Base
A Proton acceptor
Alkali
A soluble base
Oxidation state
The states of oxidation or reduction shown by an element in its chemistry
First ionization energy
The energy required to remove 1 electron from every atom in 1 mole of gaseous atoms to form a mole of gaseous 1+ ions
X –> X^+ + e^–
Electron Orbital
a subdivision of a sub shell and shell. Each orbital is defined by its energy, shape and direction in space. Each orbital contains up to two electrons.
Electron Shell
An energy level representing the distance of a group of electrons from the nucleus of an atom.
Ionic bond
A bond formed by the electrostatic forces of attraction between a positively charged ion and a negatively charged ion
Dative covalent bond
A bond formed when one atom contributes both electrons in a covalent bond ( forms a shared pair of electrons)
covalent bond
A bond formed by the attraction between positive charges in the nuclei and the negative charge on the shared electron pair.
Electronegativity
The measure of the pull of an atom on a pair of electrons in a chemical bond
Permanent dipole
An intermolecular force between two polar molecules
