chapter 7 and chapter 8 flash cards chemistry
what is true about the properties of alloys
they are often more SUPERIOR to those of their component elements
what is unique about the electrons in a metal?
they move freely from one part of the metal to the other (sea of electrons)
O2 represents two oxygen atoms that are bonded together. is this monatomic yes or no??? why?
NO, because it is not existing alone in nature...
Note that the name of an *ANION* of a nonmetallic element is ________ the same as the *ELEMENT* name
NOT
A _______________ shows the numbers of atoms of each element in the smallest representative unit of a substance.
chemical formula
The ______________________ of an ionic compound refers to a ratio known as a formula unit.
chemical formula
A covalent bond in which one atom contributes both bonding electrons is a ______________, and an example??
coordinate covalent bond example: carbon monoxide
The _________________ of an ion is the number of ions of opposite charge that surround the ion in a crystal.
coordination number
what are some of the good properties of STEELS?
corrosion resistance, ductility, hardness, toughness
O2, H2O, CO2, and N2O are explained by what kind of bonding ????
covalent
Atoms of some _____________ tend to gain electrons or share electrons with another nonmetal atom or atoms to achieve a complete octet.
nonmetals
most molecular compounds are composed of atoms of two or more _______________, unlike ionic compounds.
nonmetals
what do valence electrons mainly determine?
number of valence electrons largely determines the *CHEMICAL PROPERTIES* of an element.
anions and cations have ________ charges and attract one another by means of electrostatic forces.
opposite
A ________________ a tightly bound group of atoms that has a positive or negative charge and behaves as a unit. and an example
polyatomic ion, example is NH4+
Metals consist of closely packed _________.
cations,
__________________ are nonreactive in chemical reactions
noble gases
which type of atoms are monatomic?
noble gases
how do the valence electrons on metals hold on?
they are loosely held
Atoms of some *NONMETALS* tend to _____(1)______ electrons or ____(2)_____ electrons with atoms to achieve a complete octet.
(1) GAIN (2) SHARE
Atoms of *METALS* tend to _____(1)_______ their valence electrons, leaving a complete octet in the next-_______(2)______ energy level.
(1) LOSE (2) LOWEST
Atoms of nonmetallic elements attain noble-gas electron configurations more easily by ____(1)______ electrons than by ____(2)______ them because ...... why?
(1) gaining (2) losing because.... these atoms have relatively full valence shells.
the chemical formula of a molecular compound is called the __________(1)________, which also tells how many _____(2)____ of each _____(3)______ a substance contains.
(1) molecular formula (2) atoms (3) element
Atoms of _____(1)_____ and ______(2)______ form ___(3)___ by *gaining enough valence electrons* to attain the electron configuration of the nearest noble gas.
(1) nonmetals (2) metalloids (3) anions
Crystalline structure of metals: FACE- centered cubic arrangement, every atom has ____(1)____ neighbors.
(1) twelve
Crystalline structure of metals: HEXAGONAL close-packed arrangement, every atom also has __(1)___ neighbors
(1) twelve
crystalline structure of metals: (1)__________-____________ cubic structure, every atom (EXCEPT those on the *SURFACE*) has ____(2)_____ neighbors.
(1)body centered (2) eight
The most common ____(1)____ are those produced by the loss of valence electrons from metal atoms. Most of these atoms have ______(2)______ valence electrons, which are easily removed.
(1)cations (2) 1 or 3
If an ionic crystal is struck with pressure, the blow tends to push the _____(1)_____ ions closer together. The ______(1)______ ions _____(2)______ one another, and the crystal _______(3)______.
(1)positive (2)repel (3) shatters
what are the properties of ionic compounds?
-*crystalline solids* at room temperature. -*stable structure* (DUE TO --> each ion being strongly ATTRACTED to its neighbor) -they generally have *high melting points*
The name of the anion TYPICALLY ends in
-ide
Metals vs nonmetals; which one loses and which one gains valence electrons in an ionic compound?
-metals lose valence electrons when forming an ionic compound. -nonmetals gain valence electrons.
1) Cations of *Group 1A* elements ALWAYS have a charge of _______. 2) Cations of *Group 2A* elements ALWAYS have a charge of _______.
1) 1+ 2) 2+ , example: Mg^2+ + 2e- <---- This looks the way it does because it is maintaining "being neutral" so to say, in that, it lost two electrons (2e-), however it makes it more electrically positive, hence the 2+.
A large quantity of ______(1)______ is ______(2)_______ when hydrogen atoms combine to form hydrogen molecules.
1) heat 2) released
gas, solid, or liquid at room temperature ??? 1) Water 2) Carbon dioxide 3) nitrous oxide
1) liquid 2) gas 3) gas
Which of the following models can describe the valence electrons of metals? A. A body-centered cube B. Octets of electrons C. A rigid array of electrons D. A sea of electrons
A. A body-centered cube B. Octets of electrons C. A rigid array of electrons *D. A sea of electrons*
True or False: A strong covalent bond has a low bond dissociation energy.
False. A large bond dissociation energy corresponds to a strong covalent bond.
which *chemist* invented the rule to which were why atoms FORM certain kinds of IONS and MOLECULES. (otherwise known as the OCTET RULE)
Gilbert Lewis
Are ions able to conduct electricity, if so, how and what is true about the ions ???
Ionic compounds also conduct electric current if they are dissolved in water. When dissolved, the ions are free to move about in the solution.
Describe how ionic compounds exist as, in terms of their form and structure.
Ionic compounds do not exist as discrete units, but as collections of positively and negatively charged ions arranged in repeating patterns.
pseudo noble-gas electron configuration example??? explanation?
It refers to elements having 18 electrons instead of just 8 in their *OUTERMOST* electron configuration when they lose or gain electrons; for example when COPPER removes the one electron that it has in its outermost shell to reach the "octet rule", it ends up with 18 in the outermost shell instead because that specific shell can hold up to 18. EXAMPLE: copper 1+ or Cu ^ 1+ http://images.slideplayer.com/28/9331115/slides/slide_18.jpg
Do all atoms joined in covalent bonds donate electrons to the bond?
No. In coordinate covalent bonds, the shared electron pair comes from one of the bonding atoms.
Do resonance structures accurately represent actual bonding?
No. Resonance structures are a way to envision the bonding in certain molecules. The actual bonding is a hybrid, or mixture, of the extremes represented by the resonance forms.
Are molecules that do not obey the octet rule necessarily unstable?
No. There are molecules like NO2 that do not obey the octet rule, but that are stable, naturally occurring molecules.
READ THIS AND KNOW IT:
The octet rule cannot be satisfied in molecules whose total number of valence electrons is an odd number. There are also molecules in which an atom has less, or more, than a complete octet of valence electrons. SUCH AS NO2 -Some molecules with an even number of valence electrons, such as some compounds of boron, also fail to follow the octet rule. A few atoms, especially phosphorus and sulfur, expand the octet to ten or twelve electrons. Sulfur hexafluoride (SF6) is an example.
What representative units define molecular compounds and ionic compounds?
The representative unit of a *molecular compound* is a MOLECULE. REMEBER: A *molecule* is made up of two or more atoms that act as a unit, such that found in an ionic compound For an *ionic compound*, the smallest representative unit is a FORMULA UNIT
-carbon bonds help explain the stability of carbon compounds, HOW?
They are unreactive partly because the dissociation energy is high. *carbon single bond has a bond dissociation energy of 347 kJ/mol*
How do you find the number of valence electrons in an atom of a *representative* element?
Valence electrons are the electrons in the highest occupied energy level of an element's atoms. *SIMPLY LOOK AT THE GROUP NUMBER*
why are metals malleable? (in the matter that pressure may have been applied)
When a metal is subjected to pressure, the *metal cations* easily slide past one another
When a metal is subjected to pressure, the metal ____________ easily slide past one another.
cations
When forming a compound, a sodium atom loses its one valence electron and is left with an octet in what is now its highest occupied energy level, WHAT KIND OF ION IS FORMED??
a CATION, 1+ charge
are mixtures of two or more elements, at least one of which is a metal.
alloy
________________ are important because their properties are often superior to those of their component elements.
alloys
why are metals good conductors of electric current?
because they (electrons) are free flowing in the metal
The energy required to break the bond between two covalently bonded atoms is known as the
bond dissociation energy
molten?
break down from normal structure, such that in a AQUEOUS SOLUTION
what are some properties that are not good with ionic compounds?
brittle, shatter with a force
Atoms that are held together by sharing electrons are joined by ___________________.
covalent bonds
An oxygen molecule is an example of a ___________ molecule
diatomic, (a molecule that contains two atoms)
A___________________ bond is a bond that involves two shared pairs of electrons.
double covalent
between the different electron dot structures, they used ____________________ to indicate that two or more structures are in resonance.
double head arrows
what is the difference between ductile and malleable?
ductile — that is, they can be *drawn* into *wires*. malleable --which means that they can be *hammered* or *pressed into shapes*. THIS IS TALKING ABOUT *METALS*
When a metal is subjected to pressure, the metal cations _________________________________.
easily slide past one another.
Anions and cations have opposite charges and attract one another by means of ...
electrostatic forces
As electrons enter one end of a bar of *METAL*, an ________ number of electrons leave the other end.
equal
how do metals and ionic compounds compare?
form crystal structures and conduct electricity
the lowest whole-number ratio of ions in an ionic compound is called a
formula unit
An anion is produced when an atom ______ one or more valence electrons.
gains
Many molecular compounds are ___________ or _________ at room temperature.
gases or liquids
what is the molecular FORMULA of water
h20
The ions produced when atoms of chlorine and other HALOGENS *gain electrons* are called _________ ions, what is there charge and what group are they in ????
halide, they all have a 1- charge, group 7a -All halogen atoms have seven valence electrons and need to gain only ONE electron to achieve the electron configuration of a noble gas.
All the electrons within a given group (with the exception of ______________ ) have the same number of electron dots in their structures.
helium
The structure of metal atoms??????
they are closely packaged together as closely as possible.
elements found in nature in the form of diatomic molecules include ???
hydrogen, nitrogen, and the halogens
If the atomic sizes are quite different, the smaller atoms can fit into the spaces between the larger atoms.
interstitial alloy
what are the electrostatic forces called in ionic compounds called?
ionic bonds
a compound composed of cations and anions
ionic compoud
ionic vs covalent, which one is an array and which one is a collection of either ions or molecules?
ionic compounds are found in an array of ions covalent compounds are found in a collection of molecules
what does the release of heat suggests about the product of hydrogen atoms when combining to form hydrogen molecules?
it suggest that the product is more stable than the reactants example: The covalent bond in the hydrogen molecule (H2) is so strong that it would take 435 kJ of energy to break apart all of the bonds in 1 mole (about 2 grams) of H2.
what are the units typically used for bond dissociation energy?
kJ/mol which is the energy needed to break one mole of bonds.
A positively charged ion, or cation, is produced when an atom ________ one or more valence electrons.
loses EXAMPLE of a sodium CATION (lost an electron---> Na+)
are the forces of attraction between the free-floating valence electrons and the positively charged metal ions.
metallic bonds
which type of bonds hold metals together?
metallic bonds
Atoms of ____________ tend to lose their valence electrons, leaving a complete octet in the next-lowest energy level.
metals
A compound composed of molecules is called a ___________________________________. GIVE AN EXAMPLE
molecular compound. example>> water
__________________________ tend to have relatively lower melting and boiling points than ionic compounds.
molecular compounds
The arrangement of atoms within a molecule is called its _______________________________.
molecular structure
a neutral group of atoms joined together by covalent bonds is called a ____________.
molecule
_______________ occur when it is possible to draw two or more valid electron dot structures that have the same number of electron pairs for a molecule or ion.
resonance structures, example is the OZONE molecule
Some ions formed by transition metals do not have noble-gas electron configurations, GIVE SOME EXAMPLES
silver, Krypton, xenon READ THIS: -To achieve the structure of krypton, a silver atom would have to lose eleven electrons. -To acquire the electron configuration of xenon, a silver atom would have to gain seven electrons. -Ions with charges of three or greater are uncommon.
The halogens also form _______________________ bonds in their diatomic molecules.
single covalent
Two atoms held together by sharing one pair of electrons are joined by a _________________.
single covalent bond; example--->(H:H) or (H—H)
The most important alloys today are _____________.
steels
A large bond dissociation energy corresponds to a _________ covalent bond
strong
what represents the covalent bonds as dashes and shows the arrangement of covalently bonded atoms.
structural formula
If the atoms of the components in an alloy are about the same size, they can replace each other in the crystal.
substitutional alloy
how do ionic compounds react when dissolved in water?
the ions are free to move about in the solution.
what happens when an ionic compound is struck with a hammer?
the positive ions get closer to each other and repel, causing them to shatter
what are the properties of metals?
tough, malleable, DUCTILE (they can be drawn into wires) and shiny
Some ions formed by _____________ metals do not have noble-gas electron configurations (--->*ns2np6*; fyi this is the general electron configuration of the octet rule) and are therefore exceptions to the octet rule.
transition
The charges of cations of the ______________ metals may vary
transition *example:* An atom of iron may lose two valence electrons, forming the Fe2+ cation, or three valence electrons, forming the Fe3+ cation.
a bond formed by sharing three pairs of electrons is a _____________________
triple covalent bond
known as a lone pair or a nonbonding pair.
unshared pair
what kind of electrons are typically involved in a chemical bond?
valence electrons
what type of electrons used in the ELECTRON DOT STRUCTURES?
valence electrons
when does an ION form?
when an atom or group of atoms loses or gains electrons
when can ionic compounds conduct an electric current?
when melted and dissolved in water
