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The Periodic Table. Alkali metals  Highly reactive metals in group 1A of the periodic table Alkaline earth metals  Fairly reactive metals in group 2A.

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Presentation on theme: "The Periodic Table. Alkali metals  Highly reactive metals in group 1A of the periodic table Alkaline earth metals  Fairly reactive metals in group 2A."— Presentation transcript:

1 The Periodic Table

2 Alkali metals  Highly reactive metals in group 1A of the periodic table Alkaline earth metals  Fairly reactive metals in group 2A of the periodic table Transition metals  Those elements found in the d block of the periodic table whose properties tend to be less predictable based simply on their position in the table

3 Halogens families  Highly reactive nonmetals in group 7A of the periodic table Noble gases  The group 8A elements, which are largely unreactive (inert) due to their stable filled p orbitals

4 The Periodic Table

5 Atomic radii  A measure of the size of an atom Ionic radii  A measure of the size of an atoms ion in a crystal lattice form Electronegativity  The ability of an atom to attract electrons to itself Ionization energy  The energy required to remove an electron from an atom or ion in its gaseous state

6 Knowing the Periodic Table Rows are referred to as periods Columns are referred to as families or groups Elements within a group generally have similar properties When elements are arranged in order of increasing atomic number, there are recurring physical and chemical properties  Periodic law

7 States of Matter at Room Temperature

8 Development of the Periodic Table The number of known elements drastically increased in the early 1800s In 1869, Dmitri Mendeleev from Russia and Lothar Meyer form Germany published classification systems Mendeleev is given credit for organizing elements into the periodic table

9 Development Cont. The periodic table is an arrangement of elements in which they are separated into groups based on repeating properties Mendeleev arranged the elements in order of increasing mass (there were some exceptions Ex. Te and I) It was later realized that arranging by properties, rather than mass was more accurate Mendeleev left gaps for undiscovered elements, but accurately predicted their properties

10 Modern Periodic Table In the early 1900’s Henry Moseley determine atomic numbers of each known element The modern table is arranged based on increasing atomic numbers Each period on the periodic table corresponds to a principal energy level Elements with similar chemical and physical properties end up in the same column

11 Main Chemical Families Alkali Metals Alkaline Earth Metals Transition Metals Halogens Noble gases

12 Properties of Alkali Metals (Group 1) Have metallic properties of metals Shiny luster, malleability, high thermal and electrical conductivity Soft solids at room temperature, low melting points and densities Very reactive! (Especially with water) Found as compounds in nature, never as free elements Lose an electron when they react, thus have a +1 oxidation state

13 Properties of Alkaline Earth Metals (Group 2) Soft metals Very reactive! (Less reactive than alkali metals) All except beryllium (Be) react with water Most occur naturally only in compounds When reacted, they give up 2 electrons and have a +2 oxidation state

14 Properties of Transition Metals (Groups 3-12) Most transition metals have common metallic characteristics with other elements in their families ; except zinc (Zn), cadmium (Cd), and mercury (Hg) Can exist in several common oxidation states Are likely to form complexes with unbalanced charges and excessive electrons

15 Properties of Halogens (Group 17) All halogens are nonmetals Generally poor conductors of heat and electricity Are not all found in the same state of matter The only family with all 3 states of matter At room temperature, fluorine (F) and chlorine (Cl) are gases. Bromine (Br) is a liquid. Iodine (I) and astatine (At) are solids. Very reactive (will even react with glass!) Halogens are commonly found as diatomic molecules (F 2, Cl 2 ) Gain an electron when reacted; oxidation state of -1

16 Properties of Noble Gases All gases at room temperature Odorless and colorless Very low reactivity Exist as unbound elements in nature Referred to as inert (nonreactive)

17 Trends of Atomic Radii Size of atoms is expressed as the atomic radius Atomic radii generally decrease from left to right across a period and increase from top to bottom of a group Principal quantum number (n) of outer-level electrons increases by one from period to period Ex. Elements in period 1, n=1. For period 2, n=2, and so on As n increases down a family, the average position of outer- level electrons is farther from the nucleus As a result, atoms are LARGER

18 Trends of Ionic Radii Ion  atom or group of atoms with a charge Cation  atoms that have lost 1 or more e - and have a + charge Cations are smaller in radius because they have lost e - Ex. Ca 2+ is smaller than Ca because it has lost 2 e - Anion  atoms that have gained 1 or more e - Anions are larger because they have gained e - Ex. Br - is larger than Br because it has one more e - orbiting Trends of anions and cations are similar to that of their neutral atomic radii

19 Electronegativity Trend Number of protons and the principal quantum number influence electronegativity Generally, electronegativity increases from left to right across a period (because the # of p + increases) It generally decreases from top to bottom of a group (due to outer energy level e - being farther from the nucleus

20 Ionization Energy Trend In the event of multiple e - being removed from an atom, there are different ionization energies corresponding to each e - removed The energy required to remove the first e - is referred to as the “first ionization energy” Generally, ionization energy increases from left to right across a period and decreases from top to bottom within a family

21 Ionization Energy Cont. Depends on the force of attraction the nucleus exerts on the e - Also depends on # of p + and distance of e - from the nucleus The more p + force, the more difficult to remove an e -

22 Atomic Radii Practice Arrange the following elements in order of increasing atomic radii Sodium Iron Potassium Sulfur Phosphorus

23 Ionic Radii Practice Arrange the following ion in decreasing order of ionic radii Mg 2+ F - Cu 2+ Li + O -

24 Electronegativity Practice Which of the following atoms is more electronegative? Which is less? Calcium Chlorine Explain why you chose ___ as more electronegative than ___.

25 Ionizing Energy Practice Do metals or non-metals have a higher ionizing energy? List the following elements in order of increasing ionizing energy Au Co Pd


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