atomic radius
one-half the distance between the nuclei of identical atoms that are bonded together
trend to smaller atoms across a period is caused by
the increasing positive charge of the nucleus
In general, the atomic radii of the main group elements increase
down a group
Which of the following elements has the largest atomic radius? Li, O, C,or F?
Li
Which of the following elements has the smallest atomic radius? Li, O, C,or F?
F
Of the elements Ca, Be, Ba, and Sr, which has he largest atomic radius?
Ba
Of the elements Ca, Be, Ba, and Sr, which has the smallest atomic radius?
Be
Of the elements Al, Mg, Si, and Na, which has the smallest atomic radius?
Si
ion
an atom or group of atoms that has a positive or negative charge
ionization
any process that results in the formation of an ion
ionization energy
the energy required to remove one electron from a neutral atom of an element
in general,ionization energies of the main-group elements increase
across each period
The increase in ionization energy of atoms as you go across the period is caused by
increasing nuclear charge
Among the main-group elements, ionization energies generally decrease -?- the group.
down
Each successive electron removed from an ion feels an increasingly (stronger or weaker?) effective nuclear charge.
stronger
Electron affinity
the energy change that occurs when an electron is acquired by a neutral atom
cation
a positively charged ion
anion
a negatively charged ion
valance electrons
the number of electrons in the outermost energy level
electronegativity
a measure of the ability of an atom in a chemical compound to attract electrons
electronegativity tend to (increase or decrease?) across each period
increase
electronegativity tends to (increase, decrease,?) down a group or or remain the same.
decrease
Of the elements Ga, Br, and Ca, which has the highest electronegativity?
Br
alkali metals
Any metal in Group 1A of the periodic table
alkaline earth metals
group 2A elements
characteristics of alkali metals
soft, very reactive, not found in nature as free elements
characteristics of alkaline earth metals
harder, denser and stronger than alkali metals
Hydrogen
unique element that does not appear in any group.
transition elements
Those elements occupying the d block in the center of the periodic table including most metals., groups 3-12
main-group elements
The p-block and s-block elements together
p-block elements
all the elements in group 13-18 except helium.
halogens
group 17; contains nonmetals; 7 electrons in its outermost energy level; very reactive; poor conductors of electric current; never in its uncombined form in nature; combine with most metals to form salts
metalloids
elements that have characteristics of metals and nonmetals, semiconductors, border the zigzag line, shiny, brittle, hard, at high temp- good conductors of electric current
Mendeleev
arranged the elements into rows in order of increasing mass so elements with similar properties were in the same column
periodic
recurring or reappearing from time to time
Moseley
arranged periodic table by atomic number
periodic law
(chemistry) the principle that chemical properties of the elements are periodic functions of their atomic numbers
periodic table
an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group
Noble gasses
The six are found in group 18 of the periodic table. These elements were considered to be inert gases until the 1960's, because their oxidation number of 0 prevents the noble gases from forming compounds readily. All noble gases have the maximum number o
lanthanides
shiny, metallic elements with atomic numbers 58-71 that fill the 4f orbitals
actinides
The 14 elements with atomic numbers 90 to 103, in the 2nd row of transition metals, radioactive, unstable, do not occur in nature, most are artificial
periodicity
the repeating pattern of chemical and physical properties of the elements