which group tends to form 1+ ions?
alkali metals
which group tends to form 2+ ions?
alkaline earth metals
which group tends to form 1- ions?
halogens
which group tends to not form ions or react?
noble gases
whats the opposite of electron affinity?
ionization energy
the amount of energy it takes to add an additional electron
electron affinity
_______ want additional electrons
nonmetals
why didnt more scientists know about more elements in the 1700s?
they were unable to isolate the elements from their compounds
a set of three elements with similar properties
dobereiner's triads
what pattern did dobereiner notice about the triads?
one element in each triad tended to have properties with values that fell midway between those of the other two elements
what are 2 reasons why mendeleev gets more credit for his periodic table then meyer?
mendeleev published his table first and he explained its usefulness better
what approach did mendeleev take to arranging the elements?
he arranged them by similar repeating properties
how did he eventually organize the elements?
in order of increasing atomic mass
what convinced scientists that the periodic table is a powerful tool?
they found new elements that closely matched predicted and actual properties
why did they rearrange iodine and tellurium?
b/c iodine belongs in a group with bromine and chlorine
what didnt mendeleev know?
that the atoms of each element contain a unique number of protons
how is the modern periodic table rearranged?
in order of increasing atomic number
what does each period on the periodic table correspond to?
a principal energy level
what are the elements in the same period like?
as you move left to right across the table, their properties change and their atomic number increases
where are the metals on the periodic table?
everything to the left of the stairsteps
what are the properties of nonmetals?
poor conductors of heat and electric current, not malleable, brittle
what are the properties of metals?
good conductors, solid at room temp (minus mercury), ductile, malleable
this means that it can be drawn into wires
ductile
this means that is can be hammered into thin sheets without breaking
malleable
what column are the alkali metals in?
1
what column are the alkaline earth metals in?
2
what column are the halogens in?
17
what are the noble gases?
18
the energy required to remove an electron from an atom
ionization energy
ion with a positive charge
cation
what periodic trend doesnt include noble gases?
electronegativity
why is a cation smaller than the neutral atom of that element?
b/c they have lost electrons
how many valence electrons does column 1 have? whats the charge?
1; +1 charge
how many valence electrons does column 2 have? whats the charge?
2; +2 charge
how many valence electrons does column 3 have? whats the charge?
3; +3
the ability of an atom of an element to attract electrons when the atom is in a compound
electronegativity
ion with a negative charge
anion
most electronegative element
flourine
least electronegative element
francium
size, measured from the center of the nucleus to the edge of the electron cloud
atomic radius
elements in groups 3-12?
transition metals
what is the 4f row called?
lantheneids
what is the 5f row called?
actineids
metals _______ electrons
loose
metals always have a ______ charge
positive
nonmetals always have a _____charge
negative
how can u indicate state on the periodic table? what are the dif ones?
by color; black is sold, red is gas, and blue is liquid
whats another name for noble gases?
inert gases
where are the representative elements on the periodic table?
groups 1A- 7A
units that form when atoms of the same element are joined to one another
molecule
measures the atomic radius
picometer
what effect does the increase in the charge of the nucleus have on the size?
it draws electrons in closer to the nucleus
an atom or group of atoms that has a negative or positive charge
ion
how do metals form ions?
by loosing 1 or more valence electrons
why does gaining an electron give you a negative charge?
bc there are more negatively charged electrons then positively charged protons
does metallic character increase or decrease across period? down a group?
decreases across a period; increases down a group
does density increase or decrease across period? down a group?
increases then decreases across a period and decreases down a group
does atomic radius increase or decrease across a period? down a group?
decreases across a period; increases down a group
does shielding effect increase or decrease across a period? down a group?
stays the same across a period; increases down a group
does ionization energy increase or decrease across period? down a group?
increases across a period; decreases down a group
does electronegativity increase or decrease across a period? down a group?
increases across a period; doesnt change down a group
when the elements are arranged in order of increasing atomic number, the elements with similar chemical and physical properties appear at regular intervals
periodic law