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