chemistry chapter 3 and 4
write the electron configuration for Ge and identify the core and valence electrons
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2 - core: 1s2 2s2 2p6 3s2 3p6 3d10 - valence: 4s2 4p2
energy ordering of a number of orbitals:
- because of penetration the sublevels of each principal level are not degenerate for multielectron atoms - in the 4th and 5th principal levels, the effects of penetration become so important that the 4s orbital is lower in energy than the 3d orbitals and the 5s orbital is lower in energy than the 4d orbitals - the energy separations between one set of orbitals and the next become smaller for 4s orbitals and beyond, and the relative energy ordering of these orbitals can actually vary among elements. these variations result in irregularities in the electron configurations of the transition metals and their ions
exceptions in the trend for first ionization energy:
- boron's is smaller than beryllium (caused by change from s to p block) - Aluminum and Gallium - nitrogen and oxygen - S and Se -Na and Cl ?
properties of nonmetals:
- can be solid, liquid or gas - poor conductors of heat and electricity - gain electrons when they undergo chemical changes - form negatively charged ions
properties of metal:
- good conductors of heat and electricity - malleable - ductility shiny - they lose electrons when they undergo a chemical change -form positively charged ions
2 different types of shielding:
- the shielfing of the outermost electrons by the core electrons and - the shielding of the outermost electrons by each other
properties of ionic compounds:
-high melting and boiling points - tendency not to conduct electricity as solids - and their tendency to conduct electricity in water
predict the charges of sulfur
-monoatomic - [Ar] 1s2 2s2 2p6 3s2 3p6
predict the charges of Al
-monoatomic - [Ne] 1s2 2s2 2p6 3s2 3p6
3 key concepts associated with the energy of an electron in the vicinity of a nucleus:
1. columb's law, which describes the interactions between charged particles 2. shielding, which describes how one electron can shield another electron from the full charge of the nucleus 3. penetration, which describes how one atomic orbital can overlap spatially with another, thus penetrating into a region that is close to the nucleus and is therefore is less shielded from nuclear charge
an aspirin tablet contains 325 mg of C9H8O4, how many of these molecules does it contain?
1.09X10^21
number of CO2 molecules in a sample of CO2 with a mass of 10.8g
1.48X10^23 CO2 molecules
how many CH2Cl2 molecules are there in 25.0 g of CH2Cl2
1.77X10^23
the lewis structure for N2has how many electrons?
10 (each N has 5 electrons, they share 3 electron pairs)
determine the mass of potassium in 35.5g of KBr
11.7g
formula mass of glucose, C6 H12 O6
180.16
the s sublevel has ____ orbital and can hold ____ electrons
1;2
most groups of the periodic table don't exhibit any definite trend in electron affinity. among the group _______metals, however, electron affinity becomes more positive as we move down the column (adding an electron becomes less exothermic)
1a
choose the correct electron configuration for Se
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4
electron configuration for bromine
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 or [Ar] 4s2 3d10 4p5
electron configuration for Mg
1s2 2s2 2p6 3s2 or [Ne]3s2
the p sublevel has ____ and can hold ____ electrons
3; 6
between 3s, 3p, and 3d which penetrates the most into inner orbitals and are the least shielded, and experience the greates effetive nuclear charge
3s; 3d electrons penetrate the least
in its compounds carbon always forms ____ bonds
4
formula mass of CO2
44.01 amu
is a 4s orbital or a 3s larger?
4s
calculate the mass of Cl in 1.00 kg CCl2F2
5.86X10^2
mass percent of Cl in CCl2F2
58.64%
the d sublevel has ____ orbitals and can hold _____ electrons
5; 10
formula mass/molar mass/atomic mass of Na2O
61.98 amu
mass percent of Cl in freon-112 (C2Cl4F2)
69.58%
the f sublevel has _____ orbitals and can hold _____ electrons
7; 14
which substance is an ionic compound a) SrI2 b) N204 c)He d)CCL4
A) SrI2
which are the larger atoms? N or Al
Al
write the electron configuration and orbital diagram for each ion and determine whether its diamagnetic or paramagnetic: Al3+
Al [Ne] 3s2 3p1 al3+ [Ne] 2s2 2p6 diamagnetic because there are no unpaired electrons
write the formula for the ionic compound between aluminum and oxygen
Al2O3 (2*-3) and (3*2-)+6
which element has a higher first ionization energy: As or Sb
As
arrange these atoms in order of increasing radius: Cs+, Ba2+, I-
Ba2+<Cs+<l-
zig zag line from ___ to ____ that divides metals and non metals
Boron, Astatine; also Ge and Sb
choose the larger atom or ion: Br- or Kr
Br-, has one fewer proton, resulting in a smaller pull on the electrons and therefore a larger radius
combustion of 30.42 g of a compound containing only carbon, hydrogen, and oxygen produces 35.21g CO2 and 14.42g H2O. what is the empirical formula of the compound?
C2H4O3
a compound is 52.14%C, 13.13%H, and 34.73% O by mass. what is the empirical formula for the compound?
C2H6O
a compound has the empirical formula CH2O and a formula mass of 120.10 amu. what is the molecular formula of the compound?
C4H8O4
what is the empirical formula of the compound with the molecular formula C10H8
C5H4
write the empirical formula of the molecular formula C4H8
CH2; divide subscripts by the greatest common factor
choose the larger atom or ion: Ca or Ca2+
Ca, has an argon core and 2 4s electrons and they are the outermost electrons and are shielded from nuclear charge by the core electrons. the Ca2+ lost its 4s electrons
write the formula for the ionic compound that forms between calcium and oxygen
CaO (2+ and 2-)
what is the correct formula for the compound that forms between calcium and sulfur
CaS
list the elements in the compound CF2CL2 in order of decreasing mass percent composition
Cl>F>C
cobalt(II) chloride hexahydrate
CoCL2*6H2O
write the electron configuration and orbital diagram for each ion and determine whether its diamagnetic or paramagnetic: Fe3+
Fe [Ar] 4s2 3d6 Fe3+ [Ar] 4s0 3d5 paramagnetic
which is the larger atom? C or Ge
Ge
list the 7 diatomic molecules:
H2, N2, O2, F2, Cl2, Br2, I2
hydrogen peroxide
H2O2
empirical and molecular formula for hydrogen peroxide:
HO; H2O2
choose the more metallic element: Ge or In
In
ionic compound for naming potassium and fluorine
KF
what is the formula for Manganese(IV) oxide
MnO2
which element has a higher first ionization energy: N or Si
N
which is the larger atom N or F?
N
ammonia
NH3
some main group metals such as ____ and _____ form more than one type of cation
Pb and Sn
name compund PCl5
Phosphorous pentachloride
which element has the higher first ionization energy: Al or S
S
write the electron configuration and orbital diagram for each ion and determine whether its diamagnetic or paramagnetic: S2-
S [Ne] 3s2 3p4 S2- [Ne] 3s2 3p6 diamagnetic
choose the more metallic element: P or Sb
Sb
choose the more metallic element: Sn or Te
Sn
arrange these elements in order of increasing first ionization energy: Cl, Sn, Si
Sn<Si<Cl
early demonstration of electron spin, involved the interaction of a beam of silver atoms with a magnetic field
Stern-Gerlach
the transition metals _____ and ______ form cations with the same charge in all of their compunds.
Zn and Ag
what is the electron configuration fro Fe2+?
[Ar] 4s0 3d6
whats the difference between ionic and molecular compounds?
a molecular compound is composed of covalently bonded molecules.
which set of 4 quantum numbers corresponds to an electron in a 4p orbital? a) n=4, l=1, m1=0, ms=1/2 b) n=4, l=3, m1=3, ms=-1/2 c) n=4, l=2, m1=0, ms=1/2 d) n=4, l=4, m1=3, ms=-1/2
a) n=4, l=1, m1=0, ms=1/2
the transfer of an electron from sodium to chlorine by itself is absorbing or giving away energy?
absorbing, endothermic
group 1a elements, have outer electron configuration that are one electron beyond a noble gas, in reactions have a 1+ charge
alkali metals
group 2a elements, 2 electrons beyond a noble gas, form a 2+ charge
alkaline earth
name compound AlCl3
aluminum chloride
moseley listed elements in order of _______ instead of atomic mass and resolved mendeleevs problem
atomic number
then number of electrons in an element is equal to its?
atomic number
a set of average bonding radii determined from measurements on a large number of elements and compounds, the radius of an atom when it is bonded to another atom and is always smaller than the van der waals radisu
atomic radius
the pattern of orbital filling where only 2 electrons of opposing sins are allowed in each orbital
aufbau principle
which species is diamagnetic? a) Cr2+ b) Zn c) Mn d) C
b) Zn
which statement is true about effective nuclear charge? a) effective nuclear charge decreases as we move to the right across a row in the periodic table b) effective nuclear charge increases as we move to the right across a row in the periodic table c) effective nuclear charge remains relatively constant as we move to the right across a row in the periodic table d) effective nuclear charge increases, then decreases, at regular intervals as we move to the right across a row in the periodic table
b) effective nuclear charge increases as we move to the right across a row in the periodic table
identify the correct trends in metallic character a) metallic character increases as we move to the right across a row in the periodic table and increases as we move down a column b) metallic character decreases as we move to the right across a row in the periodic table and increases as we move down a column c) metallic character decreases as we move to the right across a row in the periodic table and decreases as we move down a column. d) metallic character increases as we move to the right across a row in the periodic table and decreases as we move down a column
b) metallic character decreases as we move to the right across a row in the periodic table and increases as we move down a column
according to cuolombs law if the separation between two particles of the same charge is doubled, the potential energy a) twice as high as it was before the distance separation b)is one-half as high as it was before the separation c) does not change d) is one-fourth as high as it was before the separation
b)is one-half as high as it was before the separation
name BaCl2*6H2O
barium chloride hexahydrate
compound with only two elements
binary compound
a shared pair of electrons
bonding pair
name for BrO3^-
bromate
for which element is the gaining of an electron most exothermic? a) Li b) N c) F d) B
c) F
the ionization energies of an unknown third period element are shown here. identify the element IE1=786 Kj/mol; IE2=1580Kj/mol, IE3=3230 kj/mol, IE4=4360kj/mol a) Mg b) Al c) Si d) P
c) Si
which electron in S is most shielded from nuclear charge? a) an electron in the 1s orbital b) an electron in a 2p orbital c) an electron in a 3p orbital d) none of the above (all of these electrons are equally shielded from nuclear charge)
c) an electron in a 3p orbital
which atoms valence electrons experience the greatest effective nuclear charge? a. the valence electrons in Mg b. the valence electrons in Al c. the valence electrons in S
c. S Mg<Al<S
name the compound CaBr2
calcium bromide
name CaSO4*1/2H2O
calcium sulfate hemihydrate
which element has a higher first ionization energy: O or Cl
can't tell
which are the larger atoms? Al or Ge
cannot determine
choose the more metallic element: S or Br
cant tell
name CO2
carbon dioxide
when an unknown compound undergoes combustion or burning in the presence of pure oxygen
combustion analysis
CuSO4*5H2O
copper (II) sulfate pentahydrate
electrons in complete principal energy levels and those in complete d and f sublevels
core electrons
the difference between the two types of shielding:
core electrons efficiently shield electrons in the outermost principal energy level from nuclear charge, but outermost electrons do not efficiently shield one another from nuclear charge
when two atoms approach each other the electrons from one atom attach to the nucleus of another according to ______ law
coulumbs
according to ________ the attraction between a nucleus and an electron increases with increasing magnitude of nuclear charge. the higher the charge the more tightly it is held
coulumbs law
what is the charge of the ion most commonly formed by S? a) 2+ b) + c) - d) 2-
d) 2-
which element has the smallest radius? a) C b) Si c) Be d) F
d) F
which statement is true about electron shielding of nuclear charge? a) outermost electrons efficiently shield one another from nuclear charge b) core electrons efficiently shield one another from nuclear charge c) outermost electrons efficiently shield core electrons from nuclear charge d) core electrons efficiently shield outermost electrons from nuclear charge
d) core electrons efficiently shield outermost electrons from nuclear charge
first ionization energy ________ going down and ______ going across a row and effective nuclear charge _________. outermost electrons are further away
decrease, increase, increase
as we move to the right across a row or period in the periodic table metallic characteristics ____________. as we move down a column in the periodic table metallic character __________.
decrease; increases
since sodium is positive and chlorine ions are negative the potential energy increases or decreases?
decreases
when 3s,3p,and 3d orbitals have same energy
degenerate
2
di
when an atom or ion in which all electrons are paired is not attracted to an external magnetic field-it is instead slightly repelled-and we say that the atom or ions is_____
diamagnetic
is Zn2+ diamagnetic or paramagnetic?
diamagnetic because it loses its 4s electrons
the modern periodic table is credited to _______ he noticed that certain groups of elements had similiar properties. when he listed elements in order of increasing mass, these simliar properties recurred in a periodic pattern
dimitri mendeleev
name the compound P2I4
diphosphorus tetraiodide
how do you get an empirical formula from a molecular one?
divide the subscripts by the greatest common factor
for the lewis structure represent valence electrons of main group elements as....
dots surrounding the element
is a double bond or single bond stronger?
double
formula for effective nuclear charge
effective nuclear charge = actual nuclear charge - the charge shielded by other electrons
a measure of how easily an atom accepts an additional electron and is crucial to chemical bonding because bonding involves the transfer or sharing of electrons
electron affinity
the energy change associated with the gaining of an electron by the atom in the gaseous state; usually but not always negative, exothermic
electron affinity
formula that indicates the relative number of atoms in of each element in a compound
empirical formula
the orbitals within a principal level of multi-electron atom, in contrast are not degenerate their energy depends on the value of l. the lower the value of l within a principal quantum number the lower the _____ of the corresponding orbital
energy
t/f electrons generally occupy the highest energy orbitals
false, lowest
t/f ioinc compounds sometimes contain positive and negative ions
false; always
t/f a molecular compound can always be determined from its constituent elements
false; cannot because the same combination of elements may form several different molecular compounds
t/f ionization energy is always negative because removing an electron always takes energy
false; positive and endothermic
t/f in a covalent bond the atoms transfer electrons
false; share
basic unit of ionic compound, smallest electrically neutral collection of ions
formula unit
nonmetals lose or gain electrons when they undergo chemical changes?
gain
an electron in a 2p orbital has a less than or greater probability of being found closer to the nucleus that an electron in a 2s orbital? the 2s orbital is lower in energy but only when the 1s orbital is occupied, (when the 1s orbital is empty, the 2s and 2p orbitals are degenerate
greater
as the outer electron undergoes penetration into the region occupied by inner electrons, it experiences a less than or greater nuclear charge and therefore a lower energy? according to coulumbs law
greater
for main-group elements electron affinity usually becomes more negative as we move to the right. the ______ have the most negative electron affinities. however 5a elements do not follow the trend the repulsion between 2 electrons occupying the same orbital causes the electron affinity to be more positive than that for elements in the previous column
halogens
group 7a elements, one electron short of noble gas, 1- charge
halogens
always has two paired dots , duet because n=1 quantum level fills with only 2 electrons
helium
except for ______ the number of valence electrons for any main-group element is equal to its lettered group number
helium
1/2
hemi
7
hepta
6
hexa
when filling degenerate orbitals, electrons fill them singly first, with parallel spins
hunds rule
how is a compound different form a mixture of elements?
in a compound elements combine in fixed definite proportions ; in a mixture, elements can mix in any properties whatsoever
the density of elements tends to (increase/decrease) as we move down a column of the periodic table
increase
atomic radii _____ as move down a column, and ______ as we move to the right
increase, decrease
atomic radii ________ going down and ______ going across a row and effective nuclear charge _________. size of outermost occupied orbital increases
increase, decrease, increase
metallic character ________ going down and ______ going across a row and effective nuclear charge _________. ionization energy ______
increase, decrease, increase, decreases
the magnitude of the interaction between charged particles ______ as the charges of the particles ______. consequently an electron with a charge of 1- is more strongly attracted to a nucleus with a charge of 2+ than it is to a nucleus with a charge of 1+
increase; increase
as move down the periodic table the highest principal quantum number of valence electrons_______. consequently the valence electrons occupy larger orbitals, resulting in larger atoms
increases
as we move down the column in the periodic table the radius if an atom(increases/decreases)
increases
as we move down a column in the periodic table, the principle quantum number of the electrons in the outermost principal energy level ______, resulting in ______ orbitals and therefore _______ atomic radii
increases, larger, larger
as we move to the right across a row in the periodic table the effective nuclear charge experienced by the electrons in the outermost principal energy level ______, resulting in a stronger attraction between the outermost electrons and the nucleus, and _____ atomic radii
increases, smaller
first ionization energy ______ going to the right and ______ going down
increases; decreases
name for IO2
iodate
the formula of an ______ compund reflects the smallest whole number ratio of ions
ionci compound
how are ionic bonds different from covalent
ionic bonds are nondirectional and hold together an array of atoms
the energy required to move an electron from the atom or ion in the gaseous state.
ionization energy
anions are much (smaller/larger) than their corresponding neutral atoms
larger
the energy associated with the formation of a crystalline lattice of the compound from the gaseous ions
lattice energy
name the compound Pb(C2H3O2)2
lead (II) acetate
name the compound PbCl4
lead(IV) chloride
an orbital that penetrates into the region occupied by core electrons is _____ shielded from nuclear charge than an orbital that does not penetrate and therefore has a ______ energy
less, lower
a common bonding theory that explains why some combinations of atoms are stable and predicts the shape of th emolecules
lewis model
______________ predicts whether a particular set of atoms will form a stable molecule and what the molecule might look like
lewis structure
the potential energy associated with ____ charges is positive but decreases as the particles get farther apart. since systems tend toward lower potential energy like charges that are close together have high potential energy and tend to move away from each other toward lower potential energy. these charges repel each other
like charges
name the compound Li2Cr2O7
lithium dichromate
a pair only associated with one atom and therefore not involved in bonding
lone pair or nonbonding electrons
metals _____ electrons but nonmetals______
lose; gain
metal gains or loses electrons when it undergoes a chemical change?
loses, in order to obtain a noble gas
when a quantum level is completely full, the overall potential energy of the electrons that occupy that level is particularly high/low?
low
when an outer principal quantum level is full the overall potential energy of the electrons is low or high
low
according to coulumbs lawchemical bonds form to lower/raise the potential energy of the charged particles that compose atoms
lower
the 2s orbital because it experiences more of the nuclear charge due to its greater penetration is lower or greater in energy than the 2p orbital?
lower
the 4s orbital is generally _____ in energy than the 3d orbital
lower
when two electrons occupy separate orbitals of equal energy, the repulsive interaction between them is ______ than when they occupy the same orbital because the electrons are spread out over a large region of space
lower
the most stable arrangement is the one with the lowest or highest potential energy?
lowest, noble gases
name MgSO4*7H2O
magnesium sulfate heptahydrate
form for solving an equation where asked to find the mass of an element present in a given mass of a compund
mass compound--moles compound---moles element----mass element
one way to express how much of an element is in a given compound
mass percent composition
an ionic bond is between ______ and __________
metal and nonmetal
ionic compounds are usually composed of __________ and ________
metals and nonmetals
covalent bonds form _______ compounds
molecular
who has the lower melting and boiling points molecular or ionic compounds??
molecular compounds because... the covalent bonds between atoms of a molecule are much stronger than the interactions between molecules. to bring a molecular substance to a boil only the relatively weak intermolecular forces have to be overcome, so molecular compounds often have low boiling points
formula that indicates the actual number of atoms of each element in a molecule of a compound
molecular formula
1
mono
valence electrons are held more or less loosely than the core electrons?
more
in a chemical formula does the more metallic or less metallic atom go first?
more metallic, more positively charged. 2:1, 1:1, 1:4
an electron with a higher charge is held(more/less tightly) and has (higher/lower) potential energy according to coulumb's law, making it (more/less) difficult to remove, and making the atom (smaller/bigger)
more, lower, more, smaller
molecular formula = empirical formula X _____
n
the principal quantum number symbol
n
what are the 4 quantum numbers for each of the two electrons in a 4s orbital?
n=4, l=0, ml=0, ms=+12 ??
naming binary ionic compounds containing a metal that forms only one type of cation:
name of the cation metal + base name of the anion (nonmetal) -ide
name compound NCl3
nitrogen trichloride
name compund NI3
nitrogen triiodide
electron affinity ________ going down and ______ going across a row and effective nuclear charge _________.
no definite trend, decrease, increase
can solid ions move?
no only liquid
pauli exclusion principle:
no two electrons in an atom can have the same four quantum numbers. implies that each orbital can have a maximum of only two electrons with opposing spins
part of the periodic table that has full outer quantum levels and are particularly stable and unreactive
noble gases
according to ________ one way to define atomic radii is to consider the distance between nonbonding atoms that are in direct contact, determined by the solids density is twice the radius of the element. represents the radius of an atom when it is not bonded to another atom
nonbonding atomic radius, or Van der Waals radius
covalent bond is between two or more _____ and _______
nonmetals and nonmetals
systems with high potential energy tend to change in ways that lower their potential energy. systems with low potential energy tend ___________ and are stable
not to change
8
octa
john newlands organized elements into _____ in an analogy to musical notes were every 8th property elements were similiar
octaves
rule that says stable configurations is usually 8 electrons in the outermost shell
octet rule
with each row the highest principal quantum number increases by ____
one
the van der waals radius of an atom:
one-half the distance between adjacent nuclei in the atomic solid
bonding atomic radius/covalent radius for nonmetals:
one-half the distance between two of the atoms bonded together
bonding atomic radius/covalent radius for metals:
one-half the distance between two of the atoms next to each other in a crystal of the metal
an unpaired electron that has spin
paramagnetic
no two electrons in one atom can have the same four quantum numbers
pauli exclusion principle
5
penta
an ion composed of two or more atoms example: hypochlorite
polyatomic ion
any one electron in a multi-electron atom experiences both the __________ charge of the nucleus and ________ charge of other electrons
positive, negative
how to name binary molecular compounds:
prefix+name of more metallic element (generally the one with the smallest group number first, if 2 elements lie in the same group use element with greatest row number first)+prefix+base name of second element + -ide
_______ theory explains the elctronic structure of atoms, this in turn determines the properties of atoms
quantum mechanical theory
theory that explains the electronic structure of atoms, which in turn determines their properties, since family has similar properties the electronic structure should have similarities as well
quantum-mechanical theory
as you move down each column, the number of electrons in the outermost principal energy level (highest n value) ....
remains the same
when dealing with ions for main group cations, we remove the required number of electrons by?
removing in the reverse order of filling F-= 1s2 2s2 2p6
choose the larger atom or ion: S or S2-
s2- , it has same number of protons but 2 more electrons
for a given value of n, the level of energy within orbitals:
s<p<d<f
the repulsion of one electron by other electrons
screening/shielding
the inner electrons in the effective nuclear charge _____ outer electrons from the full nuclear charge
shield
the first atempt to organize these elements according to ______ was made by dobereiner who grouped the elements into triads(3 elements with similiar properties)
similiarities in their properties
cations are much (smaller/larger) than their corresponding neutral atoms
smaller
name Na2O
sodium oxide
coulombs law:
states that the potential energy of two charged particles depends on their charges and on their separation. the magnitude of the potential energy depends inversely on the separation between the charged particles.
instead of decreasing in size the radii of transition elements _______________ across each row
stays roughly the same
name the compound SrI2
strontium iodide
formula that uses lines to represent covalent bonds and shows how atoms in a molecule are connected or bonded to each other
structural formula
________ determines properties
structure
4
tetra
name compound P4 S10
tetraphosphorous decasulfide
what is formula mass
the formula mass is the sum of all the atomic masses. (number of atoms in 1st elementXitsatomic mass) + .....
naming binary ionic compounds containing a metal that forms more than one type of cation:
the name of the cation is folllowed by a roman numeral in parantheses, which indicates the charge of the metal in that particular compound. name + (roman numerals) + base name of anion + -ide
aufbau principle
the pattern of orbital filling where only 2 electrons of opposing sins are allowed in each orbital
covalent bonds are highly directional. the attraction between two covalently bonded atoms is due to....
the sharing of one or more electron pairs in the space between them, thus each bond links just one specific pair of atoms
the approximate bond length of any two covalently bonded atoms is the sum of______
their atomic radii
according to cuolombs law what happens to the potential energy of two oppositely charged particles as they get closer together?
their potential energy decreases
what are main group-elements:
those in the 2 far-left columns (groups 1A and 2A) and the 6 far-right columns (groups 3A-8A)
_______ metals usually have different charges for different compunds
transition metals
3
tri
t/f an ionic compound can always be determined from its constiuent elements
true
t/f an ionic solids lattice structure is not directional meaning forces are equal all around, requires heat to overcome it
true
t/f as the electron penetrates the electron cloud of the 1s electrons, it begins to experience the 3+ charge of the nucleus more fully because the third electron is less shielded by the intervening electrons
true
t/f atomic number increases from left to right and elements with similiar properties are aligned in columns
true
t/f chemical formulas give us a relationship between the amount (in moles) of substances, not between the masses (in grams) of them
true
t/f electrons occupy orbitals so as to minimize the energy of the atom, therefore low-energy orbitals fill before higher-energy orbitals
true
t/f forming cations always requires energy and forming anions sometimes does; the energy cost of forming one with a noble gas configuration is less than the energy payback when forming chemical bonds
true
t/f in a chemical formula the sum of the positive charges must equal the sum of the negative charges
true
t/f ionic compunds must be charge neutral
true
t/f the chemical properties of elements are largely determined by the number of valence electrons the elements contain
true
t/f the density of aluminum metal is low because the density of an aluminum atom is low
true
t/f the forming of an ionic compound gives off energy as heat, exothermic
true
t/f the mass of each successive atom increases even more than its volume does, resulting in a higher density
true
t/f the molecular formula is always a whole-number multiple of the empirical formula
true
t/f to represent ionic bonding we move electron dots from the lewis symbol of the nonmetal , so the metal becomes a sation and the nonmetal becomes an anion
true
t/f transition metals tend to lose electrons in their chemical changes, but they do not generally attain noble gas electron configurations
true
t/f when 2 or more elements combine to form a compound an entirely new substance results
true
chemical bonding involves the transfer or sharing of valence electrons between ______ or more atoms
two
molecular compounds are compose of.....
two or more nonmetals
the potential energy associated with the interaction of _____ charges is negative and becomes more negative as the particles get closer together. since systems tend toward lower potential energy, these charges therefore attract to one another
unlike charges
for main group elements theyre the electrons in the outermost principal energy level. for transition elements also count outermost as d, electrons held the most loosely
valence electrons
lewis structure:
valence electrons are represented as dots and draw lewis electron dot structure for simple lewis structures to depict molecules
when dealing with ions, for transition metal cations, how are the required number of electrons removed?
we remove the electrons in the highest n-value orbital first, even if this does not correspond to the reverse order of filling V2+ = [Ar] 4s0 3d3
hund's rule:
when filling degenerate orbitals, electrons fill them singly first, with parallel spins
periodic law as defined by mendeleev
when the elements are arranged in order of increasing mass, certain sets of properties recurr periodically.
is hydrogen a diatomic element?
yes
