Chemistry Definitions Flashcards
Mole?
• the amount of substance which contains as many elementary particles as there are atoms in 12g of carbon-12
Relative atomic mass?
• the weighted average mass of an atom compared with 1/12th of carbon-12
Relative molecular mass?
• the weighted average mass of a molecule of a compound relative to the mass of an atom of carbon 12 which has a mass of 12
Molecular formula?
• the actual number of atoms of each element in a molecule
Empirical formula?
• the simplest whole number ratio of atoms of each element present in a compound
Isotopes?
• atoms of the same element with the same number of protons but different number of neutrons
Relative isotopic mass?
• mass of the isotope compared to 1/12th of the mass of carbon-12
First ionisation energy?
• energy required to remove one electron from each atom in one mole of gaseous atoms do make one mole of gaseous uni positive ions
E.g X(g) –> X+(g) + e-
Second ionisation energy?
• the energy required to remove one electron from each unipositive ion in one mole of gaseous unipositive ions to make one mole of gaseous dipositive ions
E.g X+(g) –> X2+(g) + e-
Orbital?
A region of space that can hold 2 electrons
Electronegativity?
• the power of attraction between a bonded atom and a pair of electrons in a covalent bond
An ability of an atom to attract electrons
Covalent bond?
• shared pair of electron
Dative covalent?
• one of the bonded atoms donates both electrons being shared
Hydrogen bonding?
• The interaction between the lone pair of electrons on a nitrogen, oxygen and all fluorine atom
Ionic bond?
• The electrostatic attraction between opposite the charged ions
