Test 1 Flashcards
Atomic mass unit
1/12 the mass of a carbon-12 atom
Unit symbol “u”
Ion
Charged entity formed when an atom gains or loses one or more electrons
Cation
Positively charged ion formed by the removal of one or more electrons from the valence shell of a neutral atom
EX: metals tend to lose electrons
Anion
Negatively chargers ion formed by the addition of one or more electrons to a neutral atom
EX: non-metals tend to gain electrons
Multivalent
Property of having more than one possible valence
Polyatomic ion
An ion, made up of more than one atom, that acts as a single entity
Octet rule
States that atoms tend to gain or lose electrons to achieve a stable octet
Isotope
Form of an element where the atoms have the same number of protons as all other forms of that element, but different number or neutrons
EX: carbon-12, carbon-14
Isotopic abundance
Percentage of a given isotope in a sample of an element
Atomic mass
Weighted average of the masses of all the naturally occurring isotopes of an element
EX: % abundance of isotope 1 (mass of isotope 1) + % abundance of isotope 2 (mass of isotope 2) …
Lewis Symbol
Representation of an element consisting of the chemical symbol and dots to represent the valence electrons
Electron Dot Diagram
Atomic radius
Measurement of the size of an atom
Usually expressed in picometres (pm)
Decreases from left to right
Increases top to bottom
Ionization energy
Quantity of energy required to remove an electron from an atom or ion in the gaseous state.
Decreases down a group
Increases across a period left to right
Electrolyte
Compound that dissolves in water, producing a solution that conducts electricity
Ionic bond
Electrostatic force of attraction between a positive ion and a negative ion
EN: greater or equal to 1.7
Ionic compound
Pure substance composed of positively charged ions and negatively charged ions in a fixed ratio
Molecular compound
Pure substance made up of two or more non metallic elements
Covalent bond
The bond that results from the sharing of a pair of electrons by two atoms
Lewis structure
Lines and dots
Structural formula
Just lines
Electronegativity
Ability of an atom to attract bonding electrons to itself
Electronegativity difference
Difference in electronegativity Ed of two bonded atoms or ions
Non polar covalent bond
Covalent bond formed between atoms with identical or very similar electronegativities
EN=0
All diatomic elements
Polar covalent bond
Significantly different electronegativities
EN: between 0 and 1.7
