chapter 5 Flashcards
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valence electrons
electrons with the highest energy level and are held most loosely
electron dot diagram
diagram that shows the symbol of an element surrounded by dots which are the valence electrons
chemical bond
force of attraction that holds two atoms together as a result of rearrangement of electrons between them
ion
an atom or group of atoms with an electric charge
polyatomic ions
ions that are made up of more than one atom
ionic bond
attraction bond between two oppositely charged ions
ionic compound
a compound that consists of both positive and negative ions
chemical formula
combination of symbols that show the ratio of elements in a compound
subscript
tells the ratio of elements in a compound
crystal
the shape that is formed when ions form an orderly 3d arrangement
covalent bond
chemical bond formed when 2 atoms share electrons
molecule
neutral group of atoms joined by covalent bonds
double bond
a covalent bond but times 2
triple bond
covalent bond times 3
molecular compound
compound composed of molecules
polar bond
covalent bond where electrons are shared unequally
nonpolar bond
covalent bond where electrons are shared equally
alloy
mixture made of two or more elements, at least one is a metal
metallic bond
attraction between positive metal ion and the electrons surrounding it
“sea of electrons” model of metallic bonding
explains malleability, ductility, luster, high electrical conductivity, and high thermal conductivity of solid metals
key concept: the number of valence electrons in an atom of an element determines the many properties of that element, including the ways how the atom can bond with other atoms
key concept: the periodic table reveals the underlying atomic structure of atoms, including the arrangement of electrons
key concept: ionic bonds form as a result of the attraction between positive and negative ions
key concept: when ionic compounds form, the ions come together in a way that balances out the charges on the ions. the chemical formula for the compound reflects this balance
key concept: for an ionic compound, the name of the positive ion comes first, followed by the name of the negative ion
key concept: in general, ionic compounds are hard, brittle solids with high melting points. when melted or dissolved in water, they conduct electric current
key concept: the force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons
key concept: compared to the ionic compounds, molecular compounds generally have lower melting points and boiling points. and, unlike ionic compounds, molecular compounds do not conduct electric current when melted or dissolved in water
key concept: unequal sharing of electrons causes the bonded atoms to have slight electrical charges
key concept: alloys are generally stronger and less reactive than pure metals from which they are made
key concept: metal atoms combine in regular patterns in which the valence electrons are free to move from atom to atom
key concept: the “sea of electrons” model of metallic bonding helps explain the malleability, ductility, luster, high electrical conductivity, and high thermal conductivity of solid metals
