Chemistry Chapter 7
electrons
Ionization energy generally increases across a period from left to right because _____________ are held tightly together and effective nuclear charge is greater.
covalent
Beryllium is the lightest of the alkaline earth metals. Unlike the other alkaline earths, it tends to form ____________ bonds in nature due to its large charge to size ratio.
alkaline earth metals
1. Group 2A 2. Harder, more dense, less reactive than group 1A due to smaller size and inc Zeff 3. ns2, form M2+ silicates, CO32-, SO42- 4. React less vigorously with oxygen and water than Group 1A metals. 5. Mg, Ca: most abundant and important
newland's octaves
1. By Mendeleev 2. 1860's 3. One of the first attempts at a periodic table that arranged the known elements by atomic weight. Newland noticed that if he broke up his list of elements into groups of seven - starting a new row with the eighth element - the first element in each of those groups had similar chemistry.
alkali metals
1. Group 1A -- not hydrogen 2. Soft, low density 3. Most important: Li, K, Na 4. ns1 in nature as +1 ions (M+) 5. Occurs in oceans, salt beds and minerals 6. Preparation of free metals by reduction. 7. React with oxygen - must store under oil 8. React with water: Li-moderate, Na-rapid, K-in flames, Rb and Cs explode
metals
1. Left side of the periodic table 2. Metallic character increases right to left and top to bottom 3. Form cations - due to "low" IE (often to noble gas e- configuration) 4. Form ionic compounds with nonmetals. These are redox reactions. 5. Lose electrons 6. Oxides are basic
hydrogen
1. Nonmetal 2. H2 - the odorless, colorless gas 3. H-H Bond energy 463 kJ/mol - stable 4. Isotopes: 1H (99.9%); 2H (0.01%) deuterium; 3H tritium, radioactive 5. 1s1, High IE (1312 kJ/mol) so shares e- in covalent bonds, i.e. H2O 6. Can also gain an e- (ionic bond NaH)
nitrogen
1. Nonmetal 2. N2 - odorless, colorless gas 3. 78% air - isolated from air 4. Ions: -3 to +5
oxygen
1. Nonmetal 2. O2 - odorless, colorless gas 3. 21% of air - isolated from air 4. Allotropes: O2 and O3 (ozone)
Boron
1. Nonmetal 2. Ocetet exception, rocket fuel B2H6 + O2 -> B2O3 + H2O + 2030 KJ (1979 Nobel - HC Brown)
phosphorous
1. Nonmetal 2. P4 - strained Td solid 3. Rock + sand + coke 4. Allotropes: white, red, black 5. P4O6, P4O10, H3PO3, H3PO4 6. ADP, ATP
sulfur
1. Nonmetal 2. S8 - a ring, yellow solid 3. S2- (sulfide)
silicon
1. Nonmetal 2. Solid 3. Prep: sand + coke 4. Semiconductors use SiCl4 5. SiO2 (sand, window glass) 6. Silicates: SiO42- (asbestos) 7. Silicones: - (SiOR2)n - caulk, implants
carbon
1. Nonmetal 2. Solid - covalent bonding 3. Crystalline, amorphous 4. CO, CO2 to H2CO3 (blood buffer) 5. Hydrocarbons - CH4, CH3CH3, etc.
halogens
1. Nonmetals 2. (X2): High electron affinity... X^-
noble gases
1. Nonmetals 2. Monoatomic 3. Full s and p 4. High IE, dec as move down... 5. Thought unreactive until 1962 - XeF2, XeF4, XeF6
metalloids
1. Properties are intermediate 2. Ionization energy are too high to form cations 3. Electron affinity too negative to form anions
nonmetals
1. Right side of periodic table 2. Form anions (high IE, large EA) with noble gas configuration (GN - 8) 3. In combination with other nonmetals, form molecules. HCl (g), SO2 (g) 4. Oxides are acidic. 5. Gain electrons
ns^1
Alkali metals all have the ____^__ valence electron configuration and are electropositive metals. Therefore, they lose one electron easily to form +1 ions. Alkali metals also react with halogens to form metal halides.
melting
Alkali: Cesium and francium have ____________ points below 30 ∘C. They are among the few metals that are liquid or near liquid at room temperature.
complexes
Alkali: Lithium and sodium tend to form ______________ with water. Therefore, they absorb water easily and can be used as drying agents.
ns^2
Alkaline earth metals all have the ____^__ valence electronic configuration and are electropositive. Therefore, they easily lose their two valence electrons to form +2 cations. They are also highly reactive and are not found in their elemental form in nature.
halogens
Alkaline earth metals react vigorously with _____________, forming metal halides with the general formula MX2.
oxygen
Almost all the alkaline earths react with ____________ to form the MO compound, except barium, whose size makes its form the peroxide, BaO2.
group
Each element in a particular ________ has the same outer shell electron configuration. It is only these outer, or valence, electrons that are involved in chemical reactions.
transition metal
An element belongs to Group 9. What common name might be used to describe the group to which this element belongs?
increases
Atom size ____________ down a group because of: 1. Same outer shell electron configuration 2. Increase of n (orbital "size")
decreases
Atom size generally decreases left to right across a period from left to right because: 1. Effective nuclear charge increases 2. Inner electron screen/shield outer e- from full positive charge of the nucleus.
increase
Atomic radii _____________ going down a group in the periodic table, because successively larger valence-shell orbitals are occupied by electrons.
less
Because the full attractive force of the nucleus has been decreased by the electron repulsions, we see that the effective nuclear charge is always _______ than the actual nuclear charge (Zeff < Z)
Beryllium halides are good Lewis acids, reacting readily with electron donors to form tetrahedral adducts.
Beryllium halides are good Lewis acids, reacting readily with electron donors to form tetrahedral adducts. Copy.
atomic radius
Ionization energy decreases down a group because ____________ ___________ increases down the group.
redistribution
Chemical change involves _________________ of electrons - if too much energy is required, change will not occur.
elemental form
Copper, silver, and gold have all been know since ancient times because they appear in nature in _______________ ________ and were thus discovered thousands of years ago. But the majority of elements readily form compounds and, consequently, are hard to find in nature.
compounds
Copper, silver, and gold have all been know since ancient times because they appear in nature in elemental form and were thus discovered thousands of years ago. But the majority of elements readily form _______________ and, consequently, are hard to find in nature.
anion
Electrons always added to orbital with the highest n.
cation
Electrons always removed from orbital with the highest n.
attracted, repelled
Electrons in atoms are _____________ to the nuclear, and at the same time, ____________ by other electrons in the atom.
nuclear charge
Electrons in the 1s subshell are much closer to the nucleus in Ar than in He due to the larger ___________ ________ in Ar.
filled
Elements tend to enter into chemical reactions that allow their valence electron shell to be ________. Therefore, elements that have near-empty outer shells tend to give up these electrons easily, whereas elements that have near-full electron shells will tend to more strongly attract electrons.
low
Elements with filled valence shells or subshells and ______ electron affinity tend to have Eea values near zero.
octet
Elements with less than an __________ and with high effective nuclear charge (Zeff) tend to have large negative electron affinity values.
electron affinity
Energy given off when adding an electron to a gaseous atom... trend not well established
columb's law
Explanations for periodic properties of atoms are based on ________________ _______, as the positive and negative charges are attracted to each other and like charges repulse. In atoms the combination of protons and electrons leads to several factors being present at the same time, and this makes explanations challenging as you need to consider the relative importance of different things affecting the electrostatic attractions and repulsions. These "things" include the number of protons, the degree to which they are shielded, the location of where the electrons are usually found, and the electron-electron repulsions when electrons interact with each
They get larger, just like the atoms do.
How do cations of the same charge change in radius as you move down a column in the periodic table?
distance
Ionization energy decreases down a group because positive/negative attraction decreases with increased ______________.
first ionization energy
I1... energy required to remove the highest energy electron from neutral gaseous atom... requires energy to remove an electron -- energy is positive... *X --> X^+ + electron
second ionization energy
I2... Always requires more energy that I1 - removing negative particle from positive ion.
In general, metals have lower Ei1 values than nonmetals. Exceptions to this general trend from left to right occur when a completely filled s subshell or half-filled p subshell is encountered. These stable configurations have larger than expected Eil values.
In general, metals have lower Ei1 values than nonmetals. Exceptions to this general trend from left to right occur when a completely filled s subshell or half-filled p subshell is encountered. These stable configurations have larger than expected Eil values. Copy.
acidic, metallic
Ionic oxides are typically formed between oxygen and metal and are basic in nature; this means that the least __________ oxide should contain the element that is the most ___________ in character. Metallic character increases as you move down a column and increases as you move across a row.
increases, increases
Ionic oxides are typically formed between oxygen and metal and are basic in nature; this means that the least acidic oxide should contain the element that is the most metallic in character. Metallic character _____________ as you move down a column and _____________ as you move across a row.
endothermic
Ionization energy: Electrons are attracted to the positively charged nucleus; therefore removing an electron requires energy. The process is _______________, and so ionization energies have a positive value.
s^2p^6
Main group 1A-7A
nucleus
Many properties of atoms depend on electron configuration and on how strongly the outer electrons in the atoms are attracted to the _____________... Each electron is simultaneously attracted/repelled
acidic
Molecular oxides are formed between oxygen and other nonmetals and are __________ in nature. This means that sorting the elements bonded to oxygen in order of decreasing metallic character will correspond to increasing acidity of the oxide.
decreasing, increasing
Molecular oxides are formed between oxygen and other nonmetals and are acidic in nature. This means that sorting the elements bonded to oxygen in order of _______________ metallic character will correspond to ______________ acidity of the oxide.
Moseley atomic number
Moseley correctly identified the atomic number as the number of protons in the nucleus of the atom (with X-ray frequencies and stuff)
negative
Most electron affinity values are ______________ because energy is usually released when a neutral atom gains an electron. E(ea) values become more negative with increasing tendency of the atom to accept an electron and increasing stability of the resulting anion.
lithium
Of all the alkali metals, only ____________ is small enough to react with nitrogen to form Li3N.
organometallic
Only the lighter alkali metals can react to form __________________ compounds that contain metal-carbon bonds.
screened
Outer shell electrons are ____________ from the nucleus by inner shell electrons
acid
Oxides of most nonmetals combine with water to form an ________.
water, salt
Oxides of the active metals combine with acid to form _________ and a _______.
metal hydroxides
Oxides of the active metals combine with water to form _________ __________.
heat decomposition
Oxides of the alkaline earths are obtained by _______ ________________, Δ, of the carbonates
size, reactivity
Properties of elements change, often in predictable ways, as we move across a row (period) or down a column (group) of the periodic table. These trends allow us to make predictions about physical and chemical properties such as ______ and _____________.
molecular oxides
Recall that ionic oxides are typically formed between oxygen and metal and are basic in nature, whereas _______________ __________ are formed between oxygen and other nonmetals and are acidic in nature. This means that sorting the elements bonded to oxygen in order of decreasing metallic character will correspond to increasing acidity of the oxide.
energy
Removal of successive electrons always requires more __________ (e.g., Ei3>Ei2>Ei1) because a negative electron is being removed for a successively higher positive charge. This pattern of increasing values for successive ionization energies shows a drastic increase in magnitude when an electron is removed from a completely filled energy level or one that is identical to that of a noble gas.
anion, larger
Similarly, when an atom gains electrons, the resulting __________ is larger owing to both increased electron-electron repulsions and a reduction in Zeff. The more electrons that are gained, the ___________ the ion becomes.
decreased
Simply imagine that the electron experiences a net attraction that is the result of the nuclear attraction _______________ by the electron-electron repulsions.
stability
The amount of energy required to remove an electron is related to the effective nuclear charge and the _____________ of the electron configuration of the atom.
orbital
The electron configuration of an atom tells us how many electrons are in each __________.
Hydrogen and helium both have electrons in the 1s orbital. However, helium has 2 protons and hydrogen only has 1. This means the electrons experience a stronger attraction with the nucleus and they are therefore more difficult to remove.
The ionization enegy for He is larger than the ionization energy for H. What best explains this?
Even though Be has 4 protons and H only one, the Zeff values are closer together because Be has shielding inner electrons. For H Zeff is +1 and for Be it is +2. This might lead you to think that Be would have the higher ionization energy. However, the electron in H is very close to the nucleus (in the 1s orbital) and for Be it is farther away (in the 2s). This closer distance corresponds to a stronger attraction. Also, the two electrons in the 2s orbital experience electron-electron repulsion since you have two negative charges in the same orbital. This is a minor factor, but it is another reason the ionization energy is higher in H.
The ionization energy for hydrogen is greater than the ionization energy for berylium. What best explains this?
melting point, density
The physical and chemical properties of elements often show distinct trends within the periodic table. ____________ _______ and ___________ are just two examples. Familiarity with these trends can help you to identify an unknown element based on its physical and chemical properties.
bonds
The valence shell configuration affects the ions formed by elements, as well as the number of _________ an element will form in the creation of a chemical compound.
core electron
There is a sharp increase in ionization energy when a _______ ____________ is removed.
d^10
Transition metals 1B-8B
cation, smaller
When an atom loses electrons, the resulting __________ is smaller both because the remaining electrons experience a larger Zeff and because these electrons are usually in orbitals closer to the nucleus than the electrons that were lost. The more electrons that are lost, the ____________ the ion becomes.
A. a 2p electron of a Ne atom
Which would you expect to experience a greater effective nuclear charge? A. a 2p electron of a Ne atom B. a 3s electron of a Na atom
basic
With the exception of BeO, all alkaline earth metal oxides are ________, reacting with water to form hydroxide salts, and dissolving in acid.
inner-shell electrons
Z(eff) = Z - S S = ?
# protons in the nucleus
Z(eff) = Z - S Z = ?
ionic oxides
_________ __________ are typically formed between oxygen and metal and are basic in nature; this means that the least acidic oxide should contain the element that is the most metallic in character. Metallic character increases as you move down a column and increases as you move across a row.
second
______________ electron affinity always requires energy... second electron must be force onto an already negatively charged ion
electron configuration of ions
always remove electrons from the orbital with the highest n... i.e. Li, Fe, F
light
can be used to ionize atoms and ions.
ionization energy
the amount of energy required to remove an electron from a neutral gaseous atom or gaseous ion.
effective nuclear charge
the average nuclear charge felt by an individual electron in an atom, taking into consideration the "shielding" effect of inner-shell electrons... Z(eff) = Z - S
electron affinity
the change in energy that occurs when an electron is added to a neutral isolated atom. This can be represented by the following equation
francium
the heaviest alkali metal, is radioactive. With a half-life of 22 minutes, not much is known about Fr chemistry.
