Periodic Table Topic 5

The Periodic Table 1. Classifying Elements a. Mendeleev-according to atomic MASS b. Moseley-according to atomic NUMBER 2. Periodic Law 3. Arrangement of the Periodic Table a. Period/Series-period number indicates opel b. Groups/Families-same number of valence e 4. Chemical Symbols-Table S 5. Types of Elements & Characteristics a. Metals b. Nonmetals c. Metalloids/Semi-Metals d. Noble Gases e. Transition Metals Properties of Elements-most of the information is on Table S a. Ionization Energy (IE) b. Electronegativity (EN) c. Atomic Radius d. Ionic Radius-be able to compare atomic radii vs. ionic radii Properties of Groups a. hydrogen b. Groups 1 & 2-most active metals c. Group 17-Halogens most active nonmetals d. Group 18-Noble Gases 8 valence e except He (has 2 valence e) Allotropes a. Carbon b. Oxygen c. Phosphorus Elements with no stable isotopes

As the number of known elements grew, there had to be some method of organizing this information into a useful table The first person to organize this information is Dmitri Mendeleev Dmitri Mendeleev 1834-1907 In 1869, he arranged the elements according to increasing atomic mass. Elements in the periodic table are arranged into groups based on a set of repeating properties. There were some inconsistencies Look at Te (at # 52) and I (at # 53)

When Mendeleev constructed his original table, there were Currently, there are 118 elements that make up the Periodic Table of Elements When Mendeleev constructed his original table, there were 60 known elements The Periodic Table of Elements Song

Henry Moseley did not like these inconsistencies and so decides to arrange the table using another criteria. Henry Moseley 1887-1915 In 1913, he arranged the elements by increasing atomic number and now there were no inconsistencies.

Each element is represented by a one-or two-letter chemical symbol. The first letter of a chemical symbol is always capitalized. When a second letter is used, it is lowercase. Ex.: carbon C nickel Ni If you are unsure of the symbol for an element, check Table S Some elements are represented by three letters. Their official names have not been determined by IUPAC and the letters represent their atomic number. Element 114 called ununquadium - Uuq Un = one Quad = four

Properties of Metals Metals are located to the left of the staircase More than 2/3 of the elements are metals 1. Good conductors of heat and electricity 2. Ductile-can be drawn into wires 3. Malleable-can be hammered into shape 4. Lose electrons to form positive ions (cations) 5. Luster -shiny Solid at room temperature except mercury (Hg) liquid

When elements are arranged in order of increasing Periodic Law- When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical properties. Rows (left  right) are called periods or series Look at your periodic table and look at the seven periods. The period number is the outermost principle energy level (opel) for that element Ex.: Si Look at what row it is in Row 3 = opel Columns (up and down) are called groups or families Elements in the same group have similar chemical properties because they have the same number of valence e- Look at the lower left hand corner of the box of any element. The last number is the number of valence e- Ex.: Si 2-8-4 There are 4 valence electrons

Properties of Nonmetals Nonmetals are found to the right of the staircase BUT do not include Group 18 elements 1. Insulators-do not conduct heat and electricity 2. Brittle-shatter when hammered Gain electrons to form negative ions (anions) Most are gases at room temperature, a few are solid and only one is a liquid (Br) at room temperature

Properties of Metalloids A metalloid is an element that tends to have properties that are similar to those of both metals and nonmetals Metalloids sit right along the staircase. A side of the element’s box must touch the staircase to be a metalloid The metalloids are B, Si, As, Te, At, Ge and Sb Notice Al and Po have a side of their box touching the staircase, but they are NOT metalloids

Properties of Noble Gases-Group 18 Their opel (outermost principle energy level) is filled with electrons. All of the noble gas elements have 8 valence electrons except for helium which has 2 valence electrons Because they have a filled opel, they are unreactive Look in the upper right hand corner of the box of Ne The 0 indicates that it is unreactive Now look at the box for Kr and Xe Notice the numbers…this means that they do react What type of element do noble gases react with? Elements with small atomic radius & high electronegativity Elements like Fluorine

Properties of Transition Elements Groups 3-12 The highest occupied sublevel and nearby d or f sublevel contain electrons. Solutions made of compounds that contain a transition element will have color Ex.: CuSO4 will have color because Cu is a transition element

Do not forget your seven diatomic elements BrINClHOF Br2 I2 N2 Cl2 H2 O2 F2 Diatomic elements-a molecule consisting of two atoms The rest of the elements are monatomic Monatomic elements-a molecule consisting of one atom

Properties of Elements Ionization Energy- The energy required to remove an electron from an atom in its gaseous state As you move left to right across a period, IE increases because nuclear charge increases (at. no. increases) and shielding effect remains constant so it takes more energy to remove an electron As you move down a group, IE decreases because there is an additional energy level, (size of element increases) so shielding effect is greater. Therefore, less energy is needed to remove an electron

Electronegativity- The ability of an atom to attract electrons when the atom is in a compound As you move across a period EN increases because nuclear charge increases and shielding effect remains constant so the nucleus is able to attract electrons better. As you move down a group EN decreases because there is an additional energy level, (size of element increases) so shielding effect is greater. Therefore, the nucleus is not able to attract electrons easily

Atomic Radius One-half the distance between the nuclei of two atoms of the same element when the atoms are joined As you move across a period, the radius decreases because nuclear charge increases and shielding effect remains constant so the nucleus is able to pull the electrons in closer As you move down a group, the radius increases because there is an additional energy level, (size of the element increases) so shielding effect is greater. Therefore, the element is larger.

the radius of the ion is greater than the radius of the atom Ionic Radius When a metal atom loses an electron to become a cation, the radius of the ion is less than the radius of the atom Ca > Ca+2 The more electrons lost or the fewer energy levels, the smaller the ion When a nonmetal atom gains an electron to become an anion, the radius of the ion is greater than the radius of the atom S < S2- The more electrons gained or the more energy levels, the larger the ion

Summary of Periodic Trends Across a period Ionization Energy increases Electronegativity increases Atomic Radius decreases Why? Nuclear charge increases but shielding effect remains constant. Down a group Ionization Energy decreases Electronegative decreases Atomic Radius increases Why? Additional energy level so size of atom increases and shielding effect increases

Properties of Groups Group 1-Alkali Metals Most reactive metals. Never found uncombined in nature. Always found combined with other elements Group 2-Alkaline Earth Metals Slightly less reactive than Group 1 metals. Never found uncombined in nature. Always found combined with other elements Group 17-Halogens Most reactive nonmetals. Never found uncombined in nature. Always found combined with other elements Only group with three phases of matter: F & Cl = gas Br = liquid I = solid

Group 18-Noble Gases Filled valence shell-therefore very unreactive Group 15 Triple bond between nitrogen molecules Group 16 Double bond between oxygen molecules

Opel contains electrons in the s orbitals only Groups 1 & 2- s-block elements Opel contains electrons in the s orbitals only Groups 3-12- d-block elements Outer electron configuration contains electrons in the d orbitals Group 13-18- p-block elements Outer electron configuration contains electrons in the p orbitals Lanthanide & Actinide Series- f-block elements Outer electron configuration contains electrons in the f orbitals

Allotropes One of two or more different molecular forms of an element in the same physical phase/state. Ex.: Carbon in the solid state Graphite (solid-pencils) Diamond Oxygen in the gaseous state O2 (oxygen) O3 (ozone) Phosphorus in the solid state Red phosphorus Black phosphorus Yellow/White phosphorus Same phase but different molecular structure and therefore different physical and chemical properties

Phase change from solid to gas with no visible liquid phase Remember: Sublimation- Phase change from solid to gas with no visible liquid phase Deposition- Phase change from gas to solid with no visible liquid phase What are the two substances that sublime? CO2 (dry ice) & I2 (iodine)

Elements with atomic number 83 and below have some stable isotopes and some unstable isotopes Elements with atomic number 84 and above have no stable isotopes. All of their isotopes are radioactive. f-block elements Lanthanide series Actinide series

Properties of Metals Properties of Nonmetals High Electronegativity High Ionization Energy Brittle Low melting point Low boiling point Dull Insulators Gain electrons (-ions) Fluorine (F)-best/most reactive nonmetal Luster Low Electronegativity Low Ionization Energy Malleable Ductile High melting point High boiling point Conductor of heat/electricity Lose electrons (+ ions) Francium (Fr)-best/most reactive metal

The New Periodic Table Song