PERIODIC TABLE

Essential Question: What were Mendeleev and Mosley contributions to the development of the periodic table? History: Dmitri Mendeleev (1869) Arranged elements according to increasing atomic mass Arranged elements according to increasing atomic mass Observed elements had similar chemical and physical propertiesObserved elements had similar chemical and physical properties Left spaces for elements to be discoveredLeft spaces for elements to be discovered

Henry Mosley (20th century) Arranged elements according to increasing atomic number Arranged elements according to increasing atomic number Developed the periodic law Developed the periodic law

Essential Questions: What is the periodic law? What are groups and periods? What are their significant to the periodic table? Periodic Law- the properties of the element are periodic functions of their atomic numbers There are 119 elements There are 119 elements An element is named by using 1,2, or 3 letters An element is named by using 1,2, or 3 letters Ex.: Nitrogen- N Sodium- Na Sodium- Na 1st letter is capitalized 1st letter is capitalized Elements with an atomic number greater than 108 have not been named. Elements with an atomic number greater than 108 have not been named.

Periods: Horizontal rows (1-7) Horizontal rows (1-7) The number at the beginning of each period corresponds to its principal energy level The number at the beginning of each period corresponds to its principal energy level Ex: Period 2 Li = 2-1 ( 2 energy levels) B = 2-3 (2 energy levels) Number of valence electrons increases from left to right across a period Number of valence electrons increases from left to right across a period

Essential Questions: What are valence electrons? What is their relationship to the stability of an atom? What does metal/nonmetal do with valence electrons? Valence Electrons Electrons found in the outermost energy level Electrons found in the outermost energy level Determines the chemical reactivity of element Determines the chemical reactivity of element Valence e-s = the group #Valence e-s = the group #

Octet Rule- In forming compounds, atoms tend to achieve the e- configuration of noble gases. *8 valence e-s* *8 valence e-s* Gain/ loose or share e-s to become stable. Gain/ loose or share e-s to become stable. More stability equals a decrease in energy. More stability equals a decrease in energy. Metals tend to loose their valence e-s thus achieving an octet. Metals tend to loose their valence e-s thus achieving an octet. Ex. Na=ll e-s

Non-Metals- They tend to gain e-s or share e-s w/non metals to achieve an octet. Exs: F-9 e-s 2-7. Will tend to gain 1 electron to have an electron configuration of 2-8

C- 6e 2-4 Share 4e- w/ another atom to become stable

Transition Elements:  Elements are an exception to the octet rule.  They have valence electrons in more that 1 shell.

Lewis Dot Diagrams- diagram that shows e- s as dots

Groups  Vertical columns (1-18)  Also known as families  Number of given group = number of valence electrons  Elements of same group have similar chemical properties  Metallic properties from top to the bottom of a group

Essential Questions: What are the types of elements? What are the characteristics of each type? Types of Elements metals metalloids nonmetals

Metals Comprise 80% of the elements Comprise 80% of the elements Most active metals are in group 1a and 2a (1 and 2) Most active metals are in group 1a and 2a (1 and 2) Are solid at room temperature with exception of Hg (mercury) which is a liquid Are solid at room temperature with exception of Hg (mercury) which is a liquid Are malleable Are malleable Malleable- can be hammered into a thin sheet ex: Al foil Are ductile Are ductile Ductile- can be drawn into wires ex: Cu wire Have luster (shiny) Have luster (shiny)

Good conductors of heat and electricity ( due to mobility of valence electrons) Have low ionization energy and low electronegativity values. Tend to lose electron to form positive ion with a smaller radius Table S

Nonmetals:  Are gases at room temperature, exceptions: S and P which are solids, and Br which is liquid  Is not malleable  Is not ductile  Tend to be brittle in solid phase  Lack luster (surface appears dull)  Poor conductors of electricity and heat  Has high ionization energy and low electronegativity values  Tend to gain electrons to form negative ions with radii larger than their atoms

Metalloids: (B, S, Ge, As, Sb, Te) Also called semi-metals Have properties of metals and nonmetals Fluorine Tellurium Arsenic

Essential questions: What are transition elements? What is ionization energy? What are the trends in ionization energy? Transition Elements Groups 3-12 Groups 3-12 Also known as transition metals Also known as transition metals Hard solid with high melting points, exception Hg Hard solid with high melting points, exception Hg Characterized by multiple oxidation states. Characterized by multiple oxidation states. Form ions of color Form ions of color

Ionization Energy: Energy needed to remove an electron from an atom Ex: element + energy  ion+ + electron Table S

First Ionization energy Energy need to remove 1st electron from an atom Energy need to remove 1st electron from an atom In a period, from left to right, the ionization energy increases In a period, from left to right, the ionization energy increases Each successive element in a period has one more proton, thus a greater positive nuclear charge. As the nuclear charge increases, the electron are more strongly attracted, and more energy is needed to remove them. Each successive element in a period has one more proton, thus a greater positive nuclear charge. As the nuclear charge increases, the electron are more strongly attracted, and more energy is needed to remove them. In a group form top to bottom, the ionization energy decreases, because the valence electrons in each successive element is at a higher energy level, and thus, farther away from the nucleus. It is easier to remove them the farther they are from the positive charged nucleus, and shielded by other levels of electrons. In a group form top to bottom, the ionization energy decreases, because the valence electrons in each successive element is at a higher energy level, and thus, farther away from the nucleus. It is easier to remove them the farther they are from the positive charged nucleus, and shielded by other levels of electrons.

Essential Questions: What are ions? What is a cation/anion? What is an ionic radius? Ions: Atoms or group of atoms that has a positive or negative charge Atoms or group of atoms that has a positive or negative charge Occurs when electrons are transferred between atoms Occurs when electrons are transferred between atoms Tend to lose or gain electrons to have a complete octet of valence electrons Tend to lose or gain electrons to have a complete octet of valence electrons Cation- an atom( metal) that has lost an electron Forms positive ion Forms positive ion Ex: Na 0 + energy  Na e Ex: Na 0 + energy  Na e Anion- an atom (nonmetal) that has gained an electron Forms a negative ion Forms a negative ion Ex: Cl 0 + energy  Cl -1 Ex: Cl 0 + energy  Cl -1

Ionic Radii Distance from the nucleus to the outer energy level of the ion Cation have a smaller ionic radius than the original atom Ex: Na atom- electron Na + 1 Anions have a larger ionic radius than the original atom Ex: Cl atom

Essential Questions: What is atomic radius? What are the trends in the period table? Atomic Radius ½ the distance between the nucleus of 2 atoms of the same element ½ the distance between the nucleus of 2 atoms of the same element Measured in picometer (pm 1012 pm= 1 meter) Measured in picometer (pm 1012 pm= 1 meter)  In a period from left to right, atomic radii decreases as the number of protons increases.  In a period, _________ have a larger atomic radii than nonmetals  In a group, from top to bottom, atomic radii_______ due to the increase in __________ Table S Table S

Essential Questions: What is electronegativity? What are the trends in electronegativity in the periodic table? Electronegativity Ability of an atom to attract electrons when bonded to another atom In a period from left to right, the electronegativity increases In a group the larges electronegativity values are found at the top Cesium (Cs) has the smallest electronegativity value.7 Fluorine (F) has the most electronegativity value 4.0 Noble gas ( group 18) do not have electronegativity value because they usually don’t bond Electronegativity can be used to predict the type of bond Table S

Hydrogen ► Does not have similar physical or chemical properties to the elements in group 1 ► Often loses its only valence electron to become H+ ► Can also combine with a metal to form metallic hydrides ► Can share electrons Ex: water

Essential Questions: What are the alkali metals and alkaline earth metals? What are the characteristics of each group? Essential Questions: What are the alkali metals and alkaline earth metals? What are the characteristics of each group? Tend to lose electrons easily Always found in the compound form Usually achieve the octet by losing electrons to form ionic bonds Alkali metals are usually softer than other metals. Alkali metals explode when exposed to water. Reactivity, from top to bottom increases Group 1 elements are more reactive than group 2 elements Francium (Fr) is the most reactive metal

Group 15 Change from nonmetallic properties to metallic properties form tope to bottom Change from nonmetallic properties to metallic properties form tope to bottom Ex: N, P- nonmetals; Bi- metal; As, Sb- metalloid Ex: N, P- nonmetals; Bi- metal; As, Sb- metalloid N 3 gas at room temperature, mainly due too triple bond N 3 gas at room temperature, mainly due too triple bond Group 16 Group 16 Changes from nonmetals properties with increase atomic number Changes from nonmetals properties with increase atomic number O 2 is diatomic molecule at room temperature. O 2 is diatomic molecule at room temperature.

Essential Questions: What are the halogens and the noble gases? What are the characteristics of each group? ► Also known as the halogens ► All are nonmetal, yet they tend to have metallic characteristics increase as you go down the group ► Only group with elements in 3 states of matter at room temperature,  Solid- Iodine, Astatine  Liquid- Bromine  Gas- Fluorine, Chlorine ► Astatine (At) is a radioactive element with no practical uses ► Halogens occur in nature only in compound form, because of their high reactivity

Group 18 Known as the noble gases or inert gases. Exists as monatomic molecules He has 2 electrons, but the rest of the noble gases have the stable octet Have high ionization energies and negligible electro negativities All are gases at room temperature

Noble Gases

Allotropes- Some nonmetals exist in 2 or more forms in the same phase Ex.: O 2 (gas)  have different physical/chemical properties O 3 (gas)