ch 2 - The Periodic Table Flashcards
periodic law
the chemical and physical properties of the elements are dependent, in a periodic way, upon their atomic numbers
rows of periodic table
periods; there are seven representing principal quantum numbers n = 1 through n = 7 for the s- and p-block elements
columns of periodic table
groups or families; contain elements that have the same electronic configuration in their valence shell and share similar chemical properties
A elements
known as representative elements, include groups IA through VIIIA; elements in these groups have their valence electrons in the orbitals of either s or p subshells; Roman numeral and letter designation determine the electron configuration (Group VA has five valence electrons and s2p3 configuration)
B elements
known as the nonrepresentative elements and include transition elements which have valence electrons in the s and d subshells, and lanthanide and actinide series, which have valence electrons in the s and f subshells; may have unexpected electron configurations
metals on the periodic table
found on the left and in the middle of the table, include active metals, transition metals, and lanthanide and actinide series of elements. easily give up electrons: at atomic level, have low effective nuclear charge, low electronegativity (high electropositivity), large atomic radius, small ionic radius, low ionization energy, and low electron affinity
ductility
ability of metals to be pulled or drawn into wires
malleability
ability of metals to be hammered into shapes without breaking
nonmetals
found predominantly in the upper ride side of the periodic table; little or no metallic luster, have high ionization energies, electron affinities, and electronegativities, small atomic radii, large ionic radii, usually poor conductors of heat and electricity
metalloids
stair-step group separating metals and nonmetals; also called semimetals because they share some characteristics with both metals and nonmetals; electronegativities and ionization energies lie between metals and nonmetals; reactivity depends on element they are reacting with - Boron behaves like a nonmetal with reacting with sodium (Na) but like a metal when reacting with fluorine (F)
what are the metalloids
boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po), and astatine (At)
Effective nuclear charge (Z sub eff)
the electrostatic attraction between the valence shell electrons and the nucleus; it is a measure of the net positive charge experienced by the outermost electrons; for elements in same period, this increases from left to right
principal quantum number
valence electrons separated from the nucleus by a certain number of filled principal energy levels, which can be called inner shells; increases by one each time down the elements of a given group; outermost electrons are held less tightly as this number increases
atomic radius
equal to one-half of the distance between the centers of two atoms of an element are that are briefly in contact with each other; refers to the size of a neutral element; decreases from left to right across a period and increases down a group
ionic radii
based on two generalizations: metals lose electrons and become positive, while nonmetals gain electrons and become negative; and metalloids can go in either direction, but tend to follow the trend based on which side of the metalloid line they fall on; metals closer to metalloid line have more electrons to lose to achieve the electronic configuration seen in Group VIIIA and therefore have much smaller ionic radii. Nonmetals closer to the metalloid line have larger ionic radii than nonmetals closer to the VIIIA Group.
Ionization energy (IE)
ionization potential - the energy required to remove an electron from a gaseous species; always requires an input of heat and is therefore an endothermic process. Greater Z sub eff = greater ionization energy; increases from left to right across a period and from bottom to top in a group
first ionization energy
energy required to remove the first electron and grows greater with each removal because of being removed from an increasingly positive species (second ionization energy and so on)
active metals
elements in Groups IA and IIA that have very low ionization energies; do not exist naturally in neutral forms and are always found in ionic compounds, minerals or ores
Group IA
alkali metals - losing one electron results in formation of a stable, filled valence shell; possess most of the classic physical properties of metals, except their densities are lower than those of other metals; one loosely bound electron in outermost shells; Z sub eff is very low, largest atomic radii of all elements in respective periods; low ionization energies, low electron affinities and low electronegativities. React readily with nonmetals especially halogens
Group IIA
alkaline earth metals - losing two electrons results in formation of a stable, filled valence shell; slightly higher Z sub eff than Group IA and slightly smaller atomic radii; two electrons in outer shell that are easily removed to form divalent cations
Group VIIIA
Group 18 - noble or inert gases; least likely to give up electrons; among elements with highest ionization energies; extremely low boiling point
Group VIIA
halogens - have the most electron affinity; highly reactive nonmetals with seven outer electrons; do not exist naturally in neutral state because of such high reactivity. exist as halides (ions) or diatomic molecules; high electron affinity, high electronegativity (fluorine is most)
electron affinity
refers to the energy dissipated by a gaseous species when it gains an electron; opposite concept of ionization energy and even though because it is exothermic and has a negative delta H of rxn sign, the electron affinity is the positive version of this number. Increases from left to right in a period and decreases from top to bottom in a group; noble gases have none
Electronegativity
measure of the attractive force that an atom will exert on an electron in a chemical bond; the lower the ionization energy the lower the electronegativity and vice versa with the exception of the first three noble gases; increases from left to right and bottom to top
Group VIA
chalcogens - nonmetals and metalloids in group; six electrons in outer shell and generally small atomic radii and large ionic radii; most elements here, in high doses, can be toxic or damaging
Group IB to VIIIB
Groups 3 to 12; transition metals: metals and have low electron affinities, low ionization energies and low electronegativities; high melting and boiling points; many can have different possible charged forms or oxidation states because they are capable of losing different numbers of electrons the s- and d-orbitals in valence e-s; can form many different ionic compounds; tend to associate in solution either with molecules of water (hydration complexes) or with nonmetals
subtraction frequencies
having to do with an object absorbing one color and reflecting all others causing us to perceive the absorbed color’s complementary color (blue’s compliment is yellow)
