Unit 3 (chapter 4) Flashcards
anion
negative ions formed by gaining electrons
atom
particle that consists of a nucleus of protons and neutrons surrounded by a cloud of electrons. distinguished by protons
atomic mass
mass of the atom; weighted average of the masses of all naturally occurring isotopes of an element
atomic mass unit
a unit of mass used to express atomic and molecular weights (ex: O is 15.999)
atomic mass number
mass of protons and neutrons
cation
positive ions are formed by losing electrons
covalent bond
bond between 2 nonmetals
diatomic element
elements that when uncombined with any other element exists as a bonded pair of atoms (1+7 rule)
electron
negative charge, 0 amu, found outside nucleus
formula unit
ratios of ions held together by ionic bonds
ion
- charged particle
- ions are formed from the loss or gain of electrons
- positive ions (cations) are formed by losing electrons
- negative ions (anions) are formed by gaining electrons
ionic bond
bond between one metal and one nonmetal
ionic compound
- at least one nonmetal and one metal
- made up of formula units
isotope
atoms of the same element with different masses (because of difference in number of neutrons)
- have the same physical and chemical properties
- some are radioactive, meaning their nuclei are unstable and emit radiation
- radiation is not detectable by human sense
mass number
mass of protons and neutrons