General Chemistry- The Periodic Table Flashcards
What atomic number is lithium (Li)?
3
What type of element is Lithium?
Soft Alkali metal
What are the specific characteristics of lithium?
Least dense solid element (specific gravity .53)
Does not naturally occur on earth in its elemental form
Found only in various salt compounds
Which chemist published the 1st periodic table? When?
Dmitri Mendeleev in 1869
What did Dmitri Mendeleev find?
Ordering known elements according to atomic weight revealed a pattern of periodically recurring physical and chemical properties.
Who has revised the periodic table?
Henry Moseley
How did Henry Moseley revise the periodic table?
Organized the elements based on increasing atomic number rather than atomic weight
What did the revision to the periodic table allow?
Elements to be predicted and discovered
The periodic table creates a visual representation of what?
The periodic law
What is the periodic law?
The chemical and physical properties of the elements are dependent, in a periodic way, upon their atomic number
How is the periodic table arranged?
Arranged elements into periods (rows) and groups/families (columns)
How many periods does the periodic table have?
7 periods
What do the periods represent?
The principal quantum numbers n=1 through n=7 for the s and p block elements
What do groups contain?
Elements that have the same electronic configuration in their valence shell and share similar cchemical properties.
The elements are recorded how, in the periodic table?
In their neutral state
What do the roman numerals represent?
The number of valence electrons elements in that group have in their neutral state.
What are “A” elements known as?
The representative elements
“A” elements have their valence electrons in which orbitals?
S or p subshells
What are “B” elements known as?
Nonrepresentative elements
Which groups are associated with “B” elements?
The transitions elements
Lanthanide and actinide series
Where are the valence electrons for “B” elements for transition elements and lanthanide/actinide elements?
Transition elements: s and d subhsells
Lanthanide/Actinide: s and f subshells
Which elements may have unexpected electron configurations?
The nonrepresentative elements
Examples of unexpected electron configurations?
Chromium (4s1 3d5)
Copper (4s1 3d10)
Which identification system are the elements not listed under A and B?
IUPAC
Groups are number 1 to 18
Mendeleev’s table was arranged by atomic weight, but the moder periodic table is arranged by…
Atomic number
What are the three categroies of the periodic table?
Metals
Nonmentals
Metalloids (semimetals)
Where are the metals found on the periodic table?
The left side and in the middle of the periodic table
What do the 3 categroies of metals include?
Active metals
Transitions metals
Lanthanide and actinide series
What are the characteristic of metals?
Lustrous (shiny) solids
High melting point and densities
Malleability
Ductility
What are the exceptions to some of the characteristic of metals?
Mercury- not lustrous
Lithium- Not high density
What is the definition of malleability?
The ability of metal to be hammered into shapes
What is the definition of ductility?
Ability to be pulled or drawn into wires
How is a metal defined?
A low effective nuclear charge, low electronegativity (high electron positivity), large atomic radius, small ionic radius, low ionization energy and low electron affinity.
What causes the manifestation of the characteristics of metals?
The ability of metals to easily give up electrons
The transitions metals have how many oxidation states?
2 states
What are oxidation states?
Changes when forming bonds with other atoms.
Due to loose valence electrons in metals what are metals good at?
Conductors of heat and electricity
Active metals are found in which subshell?
s subshell
Transitional metals are found in which subshells?
s and d subshells
Lanthanide/Actinide metals are found in which subshells?
s and f subshells
Which transition metals are not reactive?
Copper, nickel, silver, gold palladium, platinum
The nonreactive transition metals are good for what type of production?
Coins
Jewelery
Where are nonmetals found on the periodic table?
Predominantly on the upper right side of the periodic table.
What are the characterisitic of nonmetals?
Generally brittle in the solid state Little or no Metallic luster High ionization energies Electron affinities Electronegativities Small atomic Radii Large ionic radii Poor condiuctors of heat and electricity
The manifestation of the characteristic in nonmetals results due to what?
Inability of nonmetals to easily give up electrons
Compare nonmetals and metals, which are less unified? what properies?
Nonmetals are less unified in
Chemical
Physical properities
Where are metalloids on the periodic table?
Separating the metals and nonmetals
What is another name for metalloids?
Semimetals
Why are they called semimetals?
They share some characteristics with both metals and nonmetals.
What are the characteristics of metalloids?
Electronegativities and ionization energies lie between metals and nonmetals
Density, Melting poind, Boiling point vary widely
Combination of metallic and nonmetallic characteristics
Which elements are considered metalloids?
Boron (B) Silicon (Si) Germanium (Ge) Arsenic (As) Antimony (Sb) Tellurium (Te) Polonium (Po) Astatine (At)
Which elements are debated over whether they are included as metalloids?
Polonium
Astatine
How many key rules are there that control how valence electrons work?
3
What is the 1st key rule?
For elements in the same period, effective nuclear charge (Zeff) increase from left to right
What is the explanation of the 1st key rule?
As one moves across a period from left to right, electrons and protons are added one at a time. Positivity of the nucleus increase, and the electrons experience a stronger electrostatic pull toward the center of the atom. This causes the electron cloud to move closer and bind more tightly to the nucleus.
What is the definition of effective nuclear charge?
Electrostatic attraction between the valence shell electrons and the nucleus, which is a measure of the net positive charge experienced by the outermost elecctrons.
How is the pull from the nucleus to the valence electrons mitigated?
Nonvalence electrons that reside closer to the nucleus.
How is effective nuclear charge shown, in elements of the same period on the periodic table?
Increasing (Zeff) from left to right
What is the second key rule?
As one moves down a group, (Zeff) is remained constant, but valence electrons are held less tightly to the nucelus
What is an explanation of the second key rule?
As one moves down the group, the rpincipal quantum number increases by one each time. The valence electrons are increasily separated from the nucleus by a greater number of filled principle energy levels. This separation leads to a reduction in the electrostatic attraction between the valence electrons and the nucleus. Thus, the increasing shielding created by the inner shell electrons cancels the increased positivity of the nucleaus. So, (Zeff) stays constant, while valence electrons are held less tightly.
How is the 2nd key rule seen on the periodic table?
As you move down a group, (Zeff) is constant, while Valence electrons are more likely to react or leave an element.
What is the 3rd key rule?
Elements can gain or lose electrons in order to achieve a stable octet formation representative of the novle (inert) gases (Group ViiiA or 18) or the Octet Rule.
Which elements are stable following the octet rule?
Elements that have biological roles
Why is the octet rule not necessarily a rule?
Many exceptions to the rule.
What is the atomic radius?
Equal to one-half of the distance between the centers of two atoms of an element that are briefly in contact with each other.
How do you measure the atomic radius?
Measure the distance between two atoms of the same element and divide that distance by two.
Why can’t the radius be measured by examining a single atom?
The electrons are constatly moving around making it impossible to mark the outer boudary of the electron cloud.
From left to right on the periodic table, how does the (Zeff) change?
Increases
How does atomic radius change on a periodic table from left to right?
Decreases
How does the Atomic radius changed down a group on the periodic table?
Increases down a group
Where will the largest atom be in a group?
At the bottom
Where will the largest atom be in a period?
Group IA or Group 1
Which atom has the largest atomic radius?
Cesium
Which atom has the smallest atomic radius?
Helium
Why is Francium not considered as having the largest atomic radius?
It is exceptionally rare in nature
What are the two generalizations made to understand atomic radii?
Metals lose electrons and become positive
Nonmetals gain electrons and become negative
Metalloids can go in either direction, but tend to follow the trend based on which side of the metalloid line they fall.
How are the ionic generalizations inferred on the MCAT?
Information found in passages and questions, such as oxidation states in compounds
For nonmetals close to the metalloid line, their group number dictates what?
They require more electrons than other nonmetals to achieve the electronic configuration seen in group VIIIA
Nonmetals do _______ while the nuclei does __________.
Nonmetals gain electrons while the nuclei maintains the same charge.
What ionic radius do nonmetals close to the metalloid line possess, compared to the ionic radius of elements closer to group VIIIA?
Closer to metalloid line possess a larger ionic radius than those closer to group VIIIA
Metals are _______ in regards to their ionic radius compared to nonmetals.
Opposite
Metals closer to the metalloid line have ________ to achieve the electronic configuration seen in group VIIIA.
To lose more electrons
Metals closer to the metalloid line have _________ ionic radius compared to other metals.
Smaller
Why do metals in group IA have less reduction in radius during ionization?
Have fewer electrons to lose, thus they have a less drastic reduction in radius during ionization
What is ionization energy (IE)?
The energy required to remove an electron from a gaseous species.
What is another name for ionization energy?
Ionization potential
What is an endothermic process?
Requiring an input of heat
What is the explanation for increased ionization energy?
The greater the atom’s (Zeff) or the closer the vlaence electrons are to the nucleus, the more tightly bound they are. This makes it more difficult to remove one or more electrons, increasing the ionization energy.
How can the change in ionization energy be seen on the periodic table?
Ionization energy increases from left to right and bottom to top
What is First Ionization Energy?
The energy necessary to remove the first electron
What is Second Ionization Energy?
The energy necessary to remove the second electron from the univalent cation (X+) to form the divalent cation (X2+)
What are active metals?
Low ionization energy metals or metals in groups IA and IIA (groups 1 and 2)
What are two examples of active metals?
Lithium and Beryllium
Active metals do not _______.
Exist naturally in their neutral forms
How many electrons need to be lost in order to form stable valence shells for alkali and alkaline metals?
One electron for Alkali
Two electrons for Alkaline earth metals
Which elements rarely give up electrons?
Halogens (Group VIIA or Group 17)
How are the values for second ionization energy for group IA, Group IIA, and Subsequent monovalent cations?
Disproportionally larger for group IA
Not that much larger for Group IIA or subsequent monovalent cations
Which elements are the least likely to give up electrons?
Noble gases or inert gases
Which elements have the highest ionization energy?
Noble gases
Why is the second ionization so much larger for goup IA?
Because Group IA already lost their one valence electron making them have a noble gas like electron configuration. Pulling a second valence electron out is like trying to pull an electron out of a noble gas.
Which group is most likely to accept electrons?
Halogens
Why are Halogen’s so greedy with electrons?
By aquiring one additional electron, a halogen is able to complete its octet and achieve a noble gas configuration.
What is an exothermic process?
Expelling energy in the form of heat
What is electron Affinity?
The energy dissipated by a gaseous species when it gains an electron
What is electron affinity the opposite of?
Ionization energy
Why does (Change in (Hrxn)) have a negative sign?
Because it is an exothermic process
How is electron affinity reported?
As a positive number because it is the energy dissipated
What is the units of electron affinity?
KJ/mol
What causes a greater energy release, in regards to electron affinity?
The stronger the electrostatic pull (the higher the (Zeff) between the nucleus and the valence shell electrons, the greater the energy release when the atom gains the electron.
How is the change in electron Affinity shown on the periodic table?
Increases across the period from left to right
Decreases from top to bottom.
Which groups have a very low electron affinity?
Group IA and IIA (group 1 and 2)
Which group has a very high electron affinity?
Group VIIA (Group 17)
Do the noble gases have high electron affinity?
No, its closer to zero
Why do noble gases have low electron affinities?
They already possess a stable octet and cannot readily accept electrons
Which has the lower electron affinities, metals, nonmentals, or metalloids?
Metals
What is electronegativity?
A measure of the attractive force that an atom will exert on an electron in a chemical bond.
The greather the electronegativity of an atom, the more ________________.
It attracts electrons within a bond
What are electronegativity values related to?
Ionization energies
The lower the electronegitivity, the ________ the _________.
Lower the ionization energy
What elements are exceptions to the electronegativity and ionization rule? Why?
The first three noble gases because despite their high ionization energies, these elements have negligible electronegativity because they do not often form bonds.
What is the most common scale to meausre electronegativity?
Pauling electronegativity scale
Electronegativity is what?
A relative measure
What is the range of the scale used to find electronegativity?
0.7 to 4.0
Which are the least and most electronegative elements?
Least: Cesium
Most: Flourine
How does electronegativity change on a periodic table?
Increase across a period from left to right
Decreases from top to bottom
What are the three increaseing factors on a periodic table from left to right?
Electronegativity
Ionization energy
Electron affinity
What is the decreaseing factor on the periodic table from left to right?
Atomic radius
What are the increasing factors on a periodic table from bottom to top?
Electronegativity
Ionization energy
Electron affinity
What is the decreasing factor on the periodic table from bottom to top?
Atomic radius
Which metals are the classic physical properties of metals?
Alkali metals
What is the exception to the classic physical properities of metals seen in Alkali metals?
Density is lower than most metals
How many loosely bound electrons do the Alkali metas have in there outer most shell?
One
What trends are seen in Alkali metals?
(Zeff) values are very low Largest atomic radii of all elements in their respective periods Low ionization energies Low electron affinities Low electronegativities
Alkali metals lose one electron to form what?
Univalent cations
Alkali metals react with _________, especially _________.
Nonmetals especially Halogens
Alkaline earth metals possess what?
Many properties charateristic of metals
What makes Alkaline metals different from Alkali?
Slightly higher effective nuclear charges and thus slightly smaller atomic radii
How many valence electrons does Alkaline metals have in the outer most shell?
Two
What is formed when both electrons are removed from Alkaline metals?
Divalent Cations
Which two metal types make up Active metals? Why?
Alkali and Alkaline Earth Metals
They are so reactive that they are not naturally found in their elemental (neutal) state.
What are chalcogens?
Group VIA or Group 16
An eclectic group of nonmentals and metalloids
What are chalcogens crucial for?
Normal biological functions
Chalcogens are not as ______________________ as halogens.
Reactive
What are characteristics of Chalcogens?
Six electrons in their valence shell
Small atomic radii
Large ionic radii
Why is oxygen the most important?
It is one of the primary consituents of water, carbohydrates, and other biological molecules.
Why is sulfur important?
Component in amino acids, and vitamins
Why is selenium important?
It is a Nutrient for microorganisms
What is important to know about the rest of the Chalcogens?
They are primarily metallic and generally toxic
In high concentrations, chalcogens are what?
Toxic or damaging
What are halogens?
Group VIIA or 17
Highly reactive nonmetals with seven valeence electrons
What are Halogens desperate to do?
Complete their octets by gaining one additional electron
The physical properties of halogens are what?
Variable
Which halogens are gaseous?
F2 and Cl2
Which halogens are liquid?
Br2
Which halogens are solid?
I2
What is more uniform for the halogens?
Chemical reactivity
Due to their high electronegativities and electron affinities, Halogens are what?
Especially reactive twoard the Alkali and Alkaline earth metals
Which element has the highest electronegativity?
Flourine
Why aren’t Halogens found in their elemental state?
They are too reactive
What are the ions of Halogens called?
Halides
What is another name for noble gases?
Inert gases
What are noble gases?
Group VIIIA or Group 18
Why are noble gases also called inert gases?
They have minimal chemical reactivity due to their filled valence shells.
What do noble gases have in regards th their characterisitics?
High ionization energies,
Little or no tendency to gain or lose electrons
No measureable electronegativities
Which elements, in particular to noble gases, have no electronegativities?
He
Ne
Ar
What is extremely low in noble gases?
boiling point
At room temperatiure, what form do noble gases take?
Gas
How are noble gases usually seen throughout the world? Why?
As comercial lighting sources
Their lack of reactivity
What are transition metals?
Groups IB to VIIIB or (Groups 3-12)
Metals
What is low, in regards to characteristic in transition metals?
Electron affinities
Ionization energies
Electronegativities
What characteristics do transition metals have?
Very hard
High melting/boiling points
Quite malleable
Good conductors
Why are transition metals good conductors?
Loosely held elctrons that progressively fill the d-orbitals
What is a unique property of transition metals?
Many of them can have different oxidation states
What is an oxidation state?
Possible charged forms
Why can transition metals have different charged forms?
They are capable of losing different numbers of electrons from the s- and d-orbitals in their valence shells.
Due to the change in oxidation state of transition metals, what occurs?
Transition metals form many different ionic compounds
For transition metals, the oxidation states correspond to what?
Different colors
What are the compounds associated with each color when dealing with transition metals and their oxidation states?
Red: Cobalt (II) nitrate- Co(NO3)2 Orange: Potassium Dichromate- K2Cr2O7 Yellow: Potassium chromate- K2CrO4 Green: Nickel(II) chloride-NiCl2 Blue: Copper(II) sulfate- CuSO4 Violet: Potassium Permanganate- KMnO4
Complex transition metal ions tend to associate with what two molecules?
Water
Nonmetals
What are complex ions associated with water called?
Hydration complexes
What is an example of hydration complex, associated with transition metals?
CuSO4-5 H2O
What is an example of a complex ion associated with a nonmetal, in regards to transition metals?
[Co(NH3)6]Cl
AgCl is soluable in _______, not soluable in _______.
Aqueous ammonia (due to the formation of the complex ion [Ag(NH3)2]+ Water
The formation of complexes, for transition metals, causes what?
The d-orbitals to split into two energy sublevels
The two energy sublevels of transition metals allows complexes to do what?
Enables many of the complexes to absorb certain frequencies of light
Which frequencies give the transition meta’s complexes their characteristic color?
The frequencies not absorbed give the complexes their characteristic colors
What is subtraction frequencies?
Frequencies not absorbed
When we perceive an object as a particular color, what is it due to?
That color is not absorbed, but rather reflected by to you by the object.
What does our brain tend to mix when visualizing a transition metal?
The subtraction frequencies with their complementary color or the frequency absorbed.
