Chemistry Unit 5
Mosely
-discovered atomic number -organized the table by atomic number
Mendeleev
-first to come up w the periodic table -in order of atomic mass -pattern related to valence electrons -table had problems
simple negative ions formed from single atoms are give names that end in___?
-ide
an ion that has 3 more protons in the nucleus than there are electrons outside the nucleus will have a charge of____?
3+
what are some metalloids found on the periodic table?
B, Si, Ge, As, Sb, Te, Po, At
which element in group 1 most easily loses its electron and why?
Cesium; the valence electron is farther from the nucleus than Li or K.
what are examples of gaseous elements that exist as diatomic molecules?
H2, N2, O2,Cl2, F2
what are examples of gaseous elements that exist as monatomic species?
He, Ne, Kr, Xe, Rn, Ar
what is a metalloid?
an element whose properties are between those of metals and solid nonmetals
what are negative ions called?
anions
molecules of nitrogen gas and oxygen consist of pairs of atoms which means they..?
are said to be diatomic
what is the noble gas present in relatively large concentrations in the atmosphere?
argon
actinide series
bottom row of the bottom 2
what are some elements that are liquids at room temp?
bromine, mercury, gallium
what are positive ions called?
cations
if sodium chloride is melted and then subjected to an electric current, what is produced along with sodium metal?
chlorine gas
most substances are composed of...?
compounds (and mixtures of compounds)
ionization energy
describes the minimum amount of energy required to remove an electron from the atom into the gaseous state
what are some similarities that exist among the elements in group 7?
diatomic molecules, nonmetals, high electronegativities, all form 1- ions w metallic elements
a simple way to generate elemental hydrogen gas is to pass what through water?
electricity
ions are produced when an atom gains or loses....?
electrons
do nonmetallic elements lose or gain electrons?
gain
what are the 2 most common elemental forms of carbon?
graphite and diamond
halogens
group 17; extremely reactive
noble gases
group 18; extremely inactive
alkali metals
group 1; extremely reactive
alkaline earth metals
group 2
transition metals
group 3-12; slightly reactive
what are families of elements with similar chemical properties called?
groups
main group elements
groups 1,2,13-18
what are some similarities that exist among the elements of group 1?
highly reactive, soft, low density, metallic luster
what are some nonmetallic elements that exist as gaseous substances under ordinary conditions?
hydrogen, nitrogen, oxygen, fluorine, chlorine (all elements in group 8/ noble gases)
what are some elements that are gases at room temp?
hydrogen, nitrogen, oxygen, fluorine...
are most of the chemical elements found in nature in the chemical form or combined in compounds?
in compounds; most are too reactive to be found in the uncombined form
where are the metallic elements found on the periodic table?
left and bottom
what elements give electrons?
left hand side
which element in a given period loses electrons most easily and why?
left; the nuclear charge is the smallest and the electrons are least tightly held.
do metallic elements lose or gain electrons?
lose
a simple ion with a charge 3+ results when an atom____electrons
loses 3
which metallic elements are not solids?
mercury (@ room temp.)
what is an example of a metallic and nonmetallic elements that ordinarily occur as liquids?
metallic- mercury nonmetallic- bromine
are there more metallic elements or nonmetallic elements?
more metallic
what types of ions do the nonmetallic elements form?
negative ions (anions)
do any metallic elements ordinarily occur as gases?
no
the tendency to gain electrons is a fundamental property of the ____ elements
nonmetallic
why do the metallic elements of a given period typically have much lower ionization energies than the nonmetallic ones?
nuclear charge increases going left to right. atoms at the left have smaller nuclear charges and hold their valence electrons less tightly.
On the basis of what property are the elements arranged in order on the periodic table?
order of increasing atomic number so that elements with similar properties from vertical groups
what types of ions do the metals form?
positive ions (cations)
periodic
relating to the periodic table of the elements or the pattern of chemical properties that underlies it
what are characteristics of metallic elements?
shiny, good conductors of heat and electricity, malleable, ductile, shiny
electron affinity
the ability of an atom to attract and hold an electron -measured by the amount of energy that is released when the atom gains an electron
reactivity
the extent to which a nuclear reactor deviates from a steady state
why are the elements of group 8 referred to as the noble/inert gas elements?
they are found uncombined in nature and do not readily react with other elements
Why do nonmetallic elements pull electrons from metallic elements so effectively during a reaction?
they have a tendency to lose electrons, tend to be small in size
lanthanide series
top row of the bottom 2
where are the most nonmetallic elements located on the periodic table?
upper right side
in which direction on the periodic table are elements with similar chemical properties aligned?
vertically
what causes elements to be reactive?
when its outermost orbit isnt filled to its capacity
an isolated atom has a net charge of..?
zero
