General Chemistry chapter 2: the periodic table of elements
Mendeleev's table was arranged by atomic weight, but the modern periodic table is arranged by:`
The modern periodic table is arranged in order by atomic number.
What does the periodic law state?
the physical and chemical properties of the elements are periodic functions of their atomic numbers
What is a coordination complex?
A coordination complex consists of a central atom or ion - usually one that is metallic or the coordination center - and a surrounding array of anions, that are ligands or complexing agents.
Where are the valence electrons of active metals, transition metals, and lanthanide and actinide metals found? Where is each found on periodic table:
Active metals: S subshell: Groups 1 and 2 Transition metals: S and D subshells: Groups 3-12/13 Lanthanide and actinide: S and F subshells
Which of the following are representative elements (A) and nonrepresentative elements (B)? (Ag, Pb, Cu, N, Al, Li, Cf, Np, K, Pu, Zn, O).
Ag-B; Pb - A;, Cu-B, Al-A, Li-A, Cf, -B, Np-B, K-A, Pu-B, Zn-B, O-A
What is the difference between an atomic radius and an ionic radius? What is atomic radius trend on periodic table and why?
-ATomic radius is the size of a neutral element, and the ionic radius is dependent on how the element ionizes based on its element type and group number. -Atomic radius increases as you go to the left and down. As you move from left to right on periodic table, nucleus becomes increasingly positive, and as a result of increase in positivity, it pulls electrons more closely to it, holds them more tightly, reducing the radius. So atomic radius decreases as you move from left to right. - It also increases as you go down because as you increase quantum number, you increase number of electrons, and each subsequent energy level is further from the last, increasing the atomic radii because the nucleus holds onto the electrons less tightly as you go down, causing atomic radii to increase.
WHat are active metals?
-Active metals are found in groups 1 and 2 on periodic table. They have such low ionization energies that they are ALWAYS found in ionic compounds, minerals, or ores and do not exhist naturally in their neutral forms.
Where are alkali and alkaline earth metals found on periodic table? Why are they metallic in nature?
-Alkali: Group 1 -Alkaline: Group 2 -Metallic in nature because they can easily lose electrons from the s subshell of their valence shells.
Why is the effective nuclear charge constant in groups?
-As you move down the periodic table, the principal quantumnumber (n) increases. As it increases, the valence electrons are further away from the nucleus because of all of the subshells seperating them, reducing the electrostatic force. -So even as you go down, nucleus is more positive cus it gets more protons, the shielding and distancing of the valence electrons and the nucleus cancel out the increased positivity, causing the effective nuclear charge to be constant within groups.
What is effective nuclear charge, what is trend on periodic table, and why might this trend occur?
-As you move from left to right, tje effective nuclear charge increases. -Effective nuclear charge is the electrostatic attraction between the valence shell electrons and the nucleus of an atom. -It is a net positive charge experienced by the outermost electrons. -The atomic number determines the number of protons of an atom, so as you move from left to right across a period, the number of protons increases (as well as the number of electrons), increasing the positivity of the nucleus (protons are found in the nucleus, so the more protons you have, the more positive the nucleus). -As the positivity of the nucleus increases, the electrons in valence shell feel a stronger electrostatic pull towards the nucleus (opposites attract), so as you move from left to right, the effective nuclear charge increases.
What are the periodic trend from left to right (For atomic radius, IE, electron affinity, and electronegativity)?
-Atomic radius decreases from left to right -Ionization energy increases from left to right because protons increase, so nucleus positivity increases, so stronger bonds with electrons, so harder to remove. -Electron affinity increases from left to right - ability to hold onto electrons -Electronegativity increases from left to right - more bonds attract electrons - probs due to increase in protons
What are the priodic trends from top to bottom (for atomic radius, IE< electron affinity, and electronegativity)?
-Atomic radius increase from top to bottom -Ionization energy decreases from top to bottom - because as you down, there are more subshells in between nucleus and valence electrons, decreasing the effective nuclear charge, making it easier to remove electron, decreasing IE. -Electron affinity decreases as you go from top to bottom -Electronegativity decreases as you go from top to bottom
What group are the chalcogens in? What are they crucial for? What is the most important element in this group and why? Why is sulfur and selenium important?
-Chalcogens are found in group VIA (AKA group 16), and are crucial for normal biological functions. -Oxygen is the most important element in this group because it is one of the primary constituents of water, carbohydrates, and other biological molecules. -Sulfur is important compoenent in some amino acids and vitamins. -Selenium is an imortant nutrient for microorganisms and has a role in protection from oxidative stress.
WHat is an oxidation state? How does this apply to metals? What makes metals good conductors?
-Charges given to atom when forming bonds with other atoms. -Many metals have two or more oxidation states - valence electrons of metals are loosely held together (low electron affinity), so electrons move super freely, and as a result, metals are great conductors of heat and electricity.
What is electronegativity?
-Electronegativity is a measure of the attractive force that an atom will exert on an electron in a chemical bond. -The greater the electronegativity, the more it attracts electrons within a bond.
In each of the following pairs, which has the larger radius? (F and F-); (K and K+);
-F- has the larger radius because it is an anion, and anions are larger than their respective atoms because electron-electron repulsion forces spreads them apart and electrons outnumber the protons so the protons cannot pull the electrons as tightly towards the nucleus, cuasinf F- radius to be larger than neutral F atom. -K+ has a smaller radius than K because there is less electron-electron repulsion, so they can come closer together. Protons outnumber electrons so the protons can pull the fewer electrons tightly and closer towards the nucleus.
What is difference between first and second ionization energy?
-First ionization energy is energy required to remove on electron to form X+. -Second ionization energy is energy required to remove the second electron to from X2+.
What is the least electronegative (most electropositive) and most electronegative element?
-Fluorine is most electronegative element, with 4.0 -Cesium is least electronegative element, with 0.7
What do groups determine and what do periods determine?
-Groups determine the number of valence elecectrons and contain elements with the same electronic configuration in their valence shell. -Periods tell you the principal quantum number
For nonmetals close to the metalloid line, what does their group number dictate?
-Ionic radii deals with ions - aka cations and anions. Metals often take the cation form, and nonmetals often take the anion form. -Nonmetals close to the metalloid line require more electrons to achieve ideal electron configuration (Use Nitrogen N -3, Oxygen-2, FLuorine-1 to compare and you will see why) , and metals close to metalloid line require less electrons to achieve electron configuration (Use sodium +1, magnesium+2, and aluminum+3 to compare and you will see why).
What is the trend in ionization energy on the periodic table and why?
-Ionization energy increases from left to right and from bottom to top. -Ionization energy increases from left to right because of the effective nuclear charge - the greater the effective nuclear charger, the more tightly bound the electrons are to the nucleus, and atomic number determines positivity of nucleus and increases from left to right, so ionization energy increases from left to right because it will be harder to remove a closely bound electron. -Ionization energy increases from bottom to top, because at the top, valence electrons are closest to nucleus (less shells seperating/shielding them), making the bond super strong, so as you go up, ionization energy increases.
What is ionization energy (ionization potential)?
-Ionization energy is the energy required to remove an electron from a gaseeous species.
Based on their location in the periodic table, identify a few elements that likely possess the following properties: Luster, Poor cundtors: Good conductor but brittle
-Luster: Sodium, Magnesium and any metal -Poor COnductors: Fluorine, Oxygen and any nonmetal -Good conductor but Brittle: Boron and any metalloids
What are the metalloids in the periodic table and what do they seperate?
-Metalliods seperate the metals and nonmetals -Big Sized Genitals Assure Teasing Stories -Starts with boron and is a staircase
Where are metals found on periodic table and what do they include?
-Metals are found on the left and in the middle of the periodic table. -They include active metals, transition metals, lanthanide, and actinide series.
What are the properties of metals - phase, melting point, density, electronegativity, atomic radius, ionic radius, ionization energy.
-Metals are usually lustrous (shiny) solids under standard conditions with the exception of mercury (which is liquid). -They have high melting points -They have high densities -Can deform without breakins - malleable -Can be pulled into wires - ductile -Low electronegativity (high electropositivity) -Large atomic radius -Small ionic radius -Low ionization energy -Low electron affinity -As a result, metals EASILY give up electrons.
Why do noble gases have highest ionization energies? Under what circumstance will we see a dramatic increase in ionization energy?
-Noble gases are already stable, and have a stable electronic configuration, and giving up electron would break stability, so high iE. -Once an atom reaches stable gas configuration, or stability (half-shilled or fully-filled shells), the ionization energy required to remove the subsequent electron increases dramatically.
What group are noble gases in and why are they also known as inert gases?
-Noble gases are in group VIIIA or group 18 and they are known as inert gases because they have minimal chemical reactivity due to their filled valence shells.
Where are nonmetals found? What are their properties - ionization energy, electron affinity, electronegativity, atomic radius, ionic radius, conductivity?
-Nonmetals are found in upper right side of periodic table -High ionization energies -Strong electorn affinities -High electronegativity -Small atomic radii -Large ionic radii -Poor conductors -Hold onto electrons- dont give them up easily
DO nonmetals and metals close to metalloid line have smaller or larger ionic radii and why?
-Nonmetals close to metalloid line often require more electrons to achieve ideal electronic configuration. The nucleus has the same charge (remember number of protons stays the same), but they gain electrons, causing them to have a larger ionic radii. -Metals close to metalloid line often require LESS electrons to achieve ideal electronic configuration, but protons in nucleus remain unchanged, so they have a smaller ionic radii than others.
What is the difference between representative and nonrepresentative elements?
-Nonrepresentative elements are transition metals and lanthanide and actinide series. KNown as B. -Representative elements are groups 1A to 7A, and known as A.
How does electronegativity relate to ionization energy? What are the exceptions?
-Proportional - the lower the IE, the lower the electronegativity. The higher the IE, the higher the electronegativity. -The first three noble gases- Helium, Neon, and Argon - are exceptions because they have very high ionization energies but don't form bonds, so they have negligible electronehativities.
Is ionization energy endothermic or exothermic and why?
-Removing an electron from an atom always requires heat, so it is an endothermic process because of the input of heat.
What are the two generalizations we have to make with ionic radii?
-That metals lose electrons and become postive, and nonmetals gain electrons and become negative. -That metalloids can go in either direction, but tend to follow the trend based on which side of the metalloid they fall on. Silicon behaves more like a nonmetal because its on the nonmetal side and Germanium acts more like a metal because its on the metal side.
What is the relationship between valence electrons and reactivity?
-Valence electrons largely determine the chemical reacitvity and properties of the element because they are the furthest from the nucleus, so they have the greatest amount of potential energy.
Rank the following elements by increasing electron affinity: barium (Ba), Copper (Cu), SUlfur (S) , yttrium (Y)
1) Barium (Ba) LEAST 2) Yttrium (Y) 3) Copper (Cu) 4) Sulfur (S) MOST
Rank the following elements by decreasing first ionization energy. Calcium (Ca), Carbon (C), germanium (Ge), Potassium (K)
1) Carbon (C) MOST 2) Germanium (Ge) 3) Calcium (Ca) 4) Potassium (K) LEAST
Rank the following elements by decreasing electronegativity: antimony (Sb), neon (Ne), oxygen (O), thallium (TI).
1) Oxygen (O) MOST 2) Antimony (Sb) 3)Thallium (TI) 4) Neon (NE) - LEAST
Rank the following elements by increasing atomic radius: nionium (Nb), praseodymium (Pr), tantalum (Ta), xenon (Xe).
1) Xenon (Xe) SMALLEST 2) Nionium (Nb) 3) Tantalum (Ta) 4) Praseodymium (Pr) LARGEST
Why are most alkali metals stored in mineral oil?
Because they have high reactivity with water and air, so if you just let alkali metals ou in the open, things will randomly start exploding.
What group are halogens in and what do theyr react strongly with?
Group VIIA or group 17 and they react strongly with alkali and alkaline earth metals. They are often found as ions (halides) or diatmoic molecules.
For each of the properties listed below, write down the groups of the periodic table that exhibit those properties - High reactivity to water, Six valence electrons, Contain at least one metal, multiple oxidation states, negative oxidation states, posess a full octet in neutral state.
High reactivity to water: Alkali metals and alakline earth metals - groups 1 and 2 Six valence electrons: Groups 6 and 16 COntain at least one metal: Groups 1 through 15 Multiple oxidation states: Groups 3 through 12 Negative oxidation states: Almost all, but mainly groups 14 through 17 Possess a full octet in the neutral state: Group 18
What is the trend of nucleophilicty in protic and aprotic solvents in the periodic table?
Nucleophilicty increases down the table in polar protic solvents because hydrogen bonds are more likely to form as you go down. Nucleophilicty decreases down the table in polar aprotic solvents
If two atoms have the same electornic configuarion, how do you determine which has a larger ionic radii?
The one with less protons, because the atom with more protons is the atom with a smaller ionic radii.